The Project Gutenberg EBook of Painting by Immersion and by Compressed Air, by
Arthur Seymour Jennings
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Title: Painting by Immersion and by Compressed Air
A Practical Handbook
Author: Arthur Seymour Jennings
Release Date: July 21, 2018 [EBook #57562]
Language: English
*** START OF THIS PROJECT GUTENBERG EBOOK PAINTING BY IMMERSION ***
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_ADVERTISEMENTS._
Mander Brothers,
Wolverhampton,
ARE
EXPERTS
IN
DIPPING AND
SPRAYING PAINTS.
_Industrial
Paints and
Varnishes_
BRUSHING
DIPPING
SPRAYING
FLOWING
TUMBLING
DRYING
We specialise in all Paints, Enamels,
Japans, Lacquers, Varnishes and
other materials for the protection
and decoration of Industrial Products
of all kinds.
Our clients comprise of the principal
Manufacturers in all Trades,
and the service we are rendering to
them is ready, willing and capable
of caring for your requirements.
Experimental and Research Laboratories
are maintained to assist the
solution of any problem, whilst
there is a wealth of practical
experience to draw upon when
you consult
PINCHIN, JOHNSON & Co., Ltd.
_Paint, Varnish, Color & Enamel Manufacturers_
Minerva House, Bevis Marks, London, E.C.
_TELEGRAMS
PINCHIN, ALD, LONDON._"
_TELEPHONE
AVENUE 910_ (_3 lines_)
ESTABLISHED 1834
PAINTING BY IMMERSION AND BY COMPRESSED AIR.
[Illustration: AUTOMATIC FINISHING OF PIANOS.
LOWERING THE LOADED CARRIER INTO THE VARNISH TANK.]
_Frontispiece._
Painting by Immersion
and by Compressed Air.
_A PRACTICAL HANDBOOK_
BY
ARTHUR SEYMOUR JENNINGS, F.I.B.D.,
Editor of "The Decorator" and the "The Decorator Series of Practical
Handbooks," Author of "Commercial Paints and Painting," "Paint and
Colour Mixing," "The Painters' Pocket Book," "House Painting and
Decorating," etc., etc. Member of the Paint and Varnish Society,
The International Society for Testing Materials, etc. Examiner in
Painters' and Decorators' Work to the City and Guilds of
London Institute.
_With 150 Illustrations._
London:
OFFICES OF "THE MANAGING ENGINEER,"
93 & 94, CHANCERY LANE, W.C.
E. & F. N. SPON, LTD.,
57, HAYMARKET, LONDON, S.W.
New York:
SPON & CHAMBERLAIN.
123, LIBERTY STREET
1915
PREFACE.
In many industries the application of paint for preservative or
ornamental purposes is imperative and the item of expenditure is an
important one.
There is abundant evidence to prove that the application of paint,
either by means of dipping, spraying or other mechanical means, effects
an enormous saving of time over the old method of using brushes, while
the coats of paint are more durable and thorough.
This saving of time not only lowers the cost of production to a very
considerable extent, but it permits of a large increase in the output.
The process of "flowing-on" enamels and varnishes described in the
following pages effects an even greater saving of time in those cases
where it is applicable. The extent of this saving can be judged by
the fact that a complete coat of enamel can be given to the body of
a four-seated touring car in the almost incredibly short time of two
minutes!
These processes are used to a very large extent in many industries,
particularly those connected with metal work and engineering. In the
United States of America and in many parts of the Continent they have
reached a high degree of perfection. In Great Britain the adoption of
the methods is rapidly increasing.
It is hoped that this book will be found of service to manufacturers
who desire to ascertain whether the processes can be economically
employed in their particular industry or to those who contemplate
putting in a plant for the purpose.
It should also be helpful to those who have not been very successful
with a trial plant or who desire to bring an existing plant fully
up-to-date in its equipment. And it should be said at once that the few
cases of failure which have come to the notice of the author have been
found on investigation to be due either to the use of paint unsuitable
for the purpose or the adoption of a plant which is unfitted for the
object aimed at. Three examples may be given. In one small castings
were dipped in black paint, but it was found that "tears," or runs of
paint which did not dry properly, often occurred. Here, clearly, the
paint was at fault. It was too thick for the purpose and did not dry
hard quickly enough. The remedy was obvious.
In another case iron casements were dipped horizontally in a shallow
paint tank and the time involved in lowering them to obtain a complete
immersion was considerable. In this case the shape and size of the tank
were not suitable. It should have been deep and narrow, so that the
casements could be dipped vertically. The idea that the paint would
"settle out" if a deep tank were used was shown to be erroneous.
In a third case spraying had been tried for coating metal casements,
when it was found that the saving effected in time was more than
counter-balanced by the waste of paint. Of course, spraying was not
suitable for a job of this kind, the surface to be covered being so
very narrow. Such work is done most successfully by dipping.
The degree of perfection to which the process of dipping has been
carried in America is indicated by the fact that it is largely employed
for piano cases and many other articles requiring a perfect varnish
finish. This process is fully described in these pages and has been
successfully carried on for some years. This fact demonstrates very
clearly the possibilities of painting and varnishing by immersion.
All the principal appliances used for spraying paint, lacquer, enamel,
varnish and similar liquids have been described at length, but no
attempt has been made to prove that any one appliance is superior
to another. The details of each apparatus are given, and for the
convenience of the reader, the manufacturer's name and address. It is
suggested that those who contemplate the adoption of paint dipping, or
spraying, should get into touch with all these firms, and carefully
investigate their respective merits before coming to a decision.
The services of an expert will usually be found desirable, for,
although in engineering works much of the necessary apparatus and
accessories may be made on the premises, the exact details, such as the
kind of paint and the exact design suitable for the particular purpose,
are largely matters to be decided upon in the light of experience.
ARTHUR S. JENNINGS.
365, Birkbeck Bank Chambers,
High Holborn, W.C.
August, 1915.
CONTENTS.
CHAPTER I. PAGE
INTRODUCTION.
Increase in the Use of Painting by Dipping and Spraying--The
Remarkable Saving of Time Effected--The Durability Equal
to Brush Painting--Scope of the Subject--Whitewashing
Machines--Cost of Spraying Plant--Dipping Plant may be
very Simple--List of the Principal Products to which Paint
Spraying is Applied 1
CHAPTER II.
PAINTING BY IMMERSION.
An old Idea largely Developed in Recent Years--Simple Forms of
Paint Dipping--Painting Varnish Cans--Larger Plants--The
Tank--The Agitators--McLennan Patent--Paint Proof
Gear Box--Three Tank Plant for Different Colours--The
Rails and Hanging Apparatus--Hanging Articles after they
are Painted--Hoists--Simple Crabs and Lifting Gear--Pneumatic
Hoist--Electrical Hoist--Trolley Hoist--The
Number of Coats of Paint--Advantages of the Dipping
Process--Protecting Parts not to be Painted--Preparing
Woodwork before Painting--Filler for Iron--Stopping Holes in
Woodwork--Rubbing Down 7
CHAPTER III.
REQUIREMENTS OF DIFFERENT TRADES.
Bedsteads--Collapsible Gates--Dipping Sewing Machine Parts--Iron
Rods--Iron Window Frames or Casements--Metal
Furniture--Motor Parts (Metal)--Automatic Finishing of
Pianos--The Standard Hydraulic Immersion System--Wheels--Some
Typical Plants--Carriage Department, Woolwich
Arsenal--James Gibbons--Harrison, McGregor & Co.--Phillips
& Son--The Ford Motor Company--Marshall, Sons &
Co., Ltd.--Hayward Bros. & Eckstein, Ltd.--The Crittall
Manufacturing Co.--Excluding Dust--Heating and Ventilation
of Drying Room--A Model Drying Room 33
CHAPTER IV.
PAINT FOR DIPPING.
The Requirements of a Good Dipping Paint--Specific Gravity of
Pigments--White Dipping Paint--Gloss Paint--W. G. Scott
on Dipping Paints--Proportion of Paste and Thinners--Asbestine
--China Clay--Whiting--Zinc Oxide--Inert
Materials--Primers for Metal--Primers for Hard and Soft
Woods--Second Coat Dipping Paints--White Paste Primer--White
Dip for Metals--White Dip for Hard Wood--White
Dip for Soft Wood--White Spirit--Quantity of Paint
Required for Dipping and Spraying--Spreading Capacity
of Paints 70
CHAPTER V.
PAINTING BY COMPRESSED AIR.
The Evolution of the Apparatus Employed--Early Attempts--The
Concentric Form of Spray--Its Advantages--The Flow of
Paint--Practice Necessary--Cost of Plant--Pressure and
Volume of Air Required 78
CHAPTER VI.
TYPES OF SPRAYING APPARATUS.
The Aerograph--Electric Motor Outfit--Painting a Gasometer--Small
Aerograph--The Aeron--Uniformity of Coats--Cup
Aeron--Air Transformer--The Airostyle--Construction--"Ultra"
type--Pistol "M"--The Eureka Spraying Machine--The
Crane Eureka--The Crane "Record"--The "Invincible"--Type
"E"--Artists' Type--The Midland
Sprayer--The "Paasche" Sprayer--Larger Size--Oil and
Water Separator--Automatic Electric Controller 81
CHAPTER VII.
SUPPLY OF COMPRESSED AIR--PAINT SUPPLY--EXHAUST.
Type of Compressor--Air Main--Air Valves--Purifying Air--Small
Compressors--Water Cooling--Air Pump and Tank
Combined--General Arrangement of Accessories--The Supply
of Paint--The Exhaust Installation--Central Draught Fan--Location
of Work Cabinets--The Fumexer Spraying Cabinet--Accessories
--Turn-tables, Auto--Electric Air Heater 113
CHAPTER VIII.
STENCILS AND MASKS--THE REQUIREMENTS OF DIFFERENT
TRADES IN SPRAYING.
Protecting parts not to be Sprayed--Masks for Gas Meters--The
Hart Patent Mask--Making Stencils--Stencil Paper--Four-ounce
Stencil Metal--Zinc Stencils--Requirements of Special
Trades--Piece Work--Bookbinding--Carriages--Cycle Parts--Electrical
Work--Fancy Baskets--Gas Meters--Gas Stoves
and Ranges--Picture Frames, Picture Mouldings, etc.--Celluloid
Varnish--Spraying Ships' Hulls--Slate Enamelling--Spraying
Colour Specimens--Tramcars 141
CHAPTER IX.
SOME TYPICAL PLANTS.
Plant for Twelve Operators--The Birmingham Small Arms Co.--Airostyle
Plant for Sixteen Operators--The Davis Gas Stove
Co., Ltd.--Fletcher, Russell & Co., Ltd.--Special Machines
--Gittings, Hills and Boothby, Ltd.--The Kingsbury Manufacturing
Co., Ltd.--J. Lucas, Ltd.--The Gas Light and Coke
Co., Ltd.--The Gas Meter Co., Ltd 158
CHAPTER X.
PAINTS, LACQUERS, VARNISHES, ETC., USED IN SPRAYING.
Temperature of Spraying Room--Fine Paint must be used--Firms
who Specialize on Dipping and Spraying Paints, etc.--Stoving
Enamels--Enamels--Hints on Stoving or Baking--Black
Japan Finishes--Steel Furniture Enamels--Imitation Wood
Effects--White Work--Bedsteads, etc.--Transparent Colour
Varnishes--Safe Baking Heats of Pigment Colours--Dipping
and Spraying Compared 177
CHAPTER XI.
SPRAYING VERSUS BRUSHING.
Comparison with Brush Painting--Bronzing with Celluloid
Medium--Objections Sometimes Urged Against Spraying---Mottled
Appearance of Paint and how Avoided--Spraying
Fillers and Primers--Spraying and Dipping Compared--The
Great Saving Effected 193
CHAPTER XII.
THE ARTISTIC APPLICATION OF PAINT SPRAYING.
Artistic Work--Lining on Motors and Carriages--Relief Work
--Scumbling and Colour Glazing--Glazing--Designs for Lamp
Shades--Reds--Blues--Yellows--Greens--Browns--Greys--Scumbling
and Graining--Brush Graining--Marble Grounds--Graining
Grounds 201
CHAPTER XIII.
THE "FLOWING-ON" SYSTEM.
The Latest Method of Finishing Automobiles--Remarkable Speed
of the Method--The Apparatus--Trough Tank used in the
Process--The Kind of Paint or Japan Used--The Floco Process
--Painting Motor Bodies--Description of Modern Enamelling
Ovens for Motor Bodies--Notes on the Construction of Stoves--The
Perkins' Stove--Typical Goodyear Stove--Dipping
Trough 216
CHAPTER XIV.
LIME AND WHITEWASH SPRAYERS.
Periodical Whitewashing in Workshops Compulsory--The Wells
Sprayer--Limewhiting by Machine with 8-foot Bamboo Pole--The
Brown Sprayer--The Merryweather Sprayer--The
Tumbling Barrel Process 243
CHAPTER XV.
A PORTABLE PAINT SPRAYER FOR RAILWAY AND OTHER WORK.
The Pennsylvania Railroad System--fainting Freight Cars--Description
of Apparatus--Plan and Elevation--Detail
Drawings 250
CHAPTER XVI.
METAL SPRAYING.
Description of the Process--The Immense Field for it--The
Metal Spraying "Pistol"--Detail Drawings of Pistol--Sectional
Drawing--Diagrammatic Representation of Melting
and Spraying Jets in Action--Spraying Alloys--Cost of the
Process 255
LIST OF ILLUSTRATIONS.
PAGE
FRONTISPIECE Automatic Finishing of Pianos
Fig. 1. Section through Paint Tank 8
" 2. Stirrers and Blinds for Paint Dipping Tank 10
" 3. Longitudinal Vertical Section 10
" 4. Tank for Painting Steel Sheets 12
" 5. Paint-Proof Bearings and Gear Box 13
" 6. Shafting and Driving Gear Designed for Implements 14
" 7. Triple-tank plant 15
" 8. Joist and Wheels supporting Hanger 16
" 9. Hook for Hanging 17
" 10 to 14. Hoists and Crabs 18
" 15. Typical Hoist for Painting by Immersion 19
" 16. Morris Standard Electric Trolley Hoist 23
" 17. Electric Hoist Suitable for Heavy Goods 27
" 18. Sprayed Show Card 30
" 19. Dipping and Stoving Bedsteads 31
" 20. Immersing Mangle Frames 35
" 21. Iron Hanger 38
" 22. Carrier filled with Six Complete Pianos 39
" 23. Introductory Carrier for Piano Frame 43
" 24. Lowering Piano Cases into the Varnish Tank 47
" 25. Piano Cases nearly Immersed 49
" 26. Piano Cases wholly Immersed 51
" 27. Piano Cases about to be Dipped 53
" 28. Coach Body ready to be Dipped 55
" 29. Paint Dipping Room at Woolwich 55
" 30. Store Room, Woolwich 61
" 31. Dipping Casements at the Crittall Manufacturing Co. 61
" 32. Hook for Suspending Boxes 64
" 33. Dipping Casements at Braintree 65
" 34. Design for Show Card done by Spraying 69
" 35. The Aerograph Spraying Instrument 81
" 36. Another form of Aerograph 82
" 37. Aerograph Electric Motor Outfit 83
" 38. Painting a Gasometer 83
" 39. Aerograph for Delicate Work 85
" 40. The Aeron Sprayer 89
" 41. " " (angle barrel) 89
" 42. " " with agitator 89
" 43. " " with double nozzle head 89
" 44. The G Aeron Sprayer, with double nozzle head 89
" 45. The G Aeron Sprayer, with attachments 91
" 46. The G Aeron Sprayer, with parts disassembled 91
" 47. The G Aeron Sprayer 91
" 48. The M Aeron Sprayer 95
" 49. The M Aeron Sprayer, with Types L & M 95
" 50. Block and Tackle 95
" 51. Standard Tackle 95
" 52. Air Transformer Set 95
" 53. Air Transformer 95
" 54. Section showing Construction of Airostyle 98
" 55. Airostyle Type "Record" with union for continuous supply 99
" 56. Airostyle Type "Ultra" 101
" 57. " Pistol "M" 102
" 58. The Crane "Eureka" 103
" 59. " " "Record" 104
" 60. The "Invincible" Sprayer 105
" 61. " " with adjustable cup 105
" 65. The Midland Sprayer 108
" 66. The "Paasche" Sprayer 109
" 67. Larger "Paasche" Sprayer 110
" 68. General form of "Paasche" Sprayer 111
" 69. "Paasche" Oil and Water Separator 111
" 70. "Paasche" Automatic Electric Controller 111
" 71. Airostyle Air Compressor 115
" 72. DeVilbiss Air Compressors 115
" 73. " " " 115
" 74. " " " 115
" 75. Aerograph Air Pumps and Tank Combined 118
" 76. Aerograph Type of Air Pumps for Larger Installations 119
" 77. Airostyle Plant General Arrangement 121
" 78. "Paasche" Motor Dryer Fan 124
" 79. Airostyle Central Draught Steel Plate Fan 125
" 80. DeVilbiss Auto Cool Electric Exhaust Fan closed and
opened for cleaning 125
" 81. Sketch of Spraying Cabinets 127
" 82. Aerograph Spraying Cabinets 128
" 83. "DeVilbiss Fumexer" or Spraying Cabinet 131
" 84. " " " " 131
" 85. " " " " 131
" 86. " " " " 131
" 87. Aerograph Turntable 134
" 88. Two forms of Fumexer 135
" 89. The Fumexer in use 135
" 90. A Paasche Turntable 135
" 91. Auto Electric Air Heater 139
" 92. Masks for Gas Meter 142
" 93. The Hart Patent Mask 143
" 94. Bin for Spraying Light Articles 148
" 95. Aerostyle Plant for sixteen operators 155
" 96. Airostyle Plant showing Ventilator 155
" 97. Side Elevation of Plant for 12 operators 158
" 98. End Elevation of Plant for 12 operators 159
" 99. Plan of Figs. 84 and 85 160
" 100. Airostyle Plant installed for The Davis Gas Stove Co.,
Ltd. 161
" 101. Compressor, etc., for Airostyle Plant 165
" 102. Airostyle Plant installed for Gas Fire and Radiator
Work 165
" 103. View from one end of Messrs. Lucas, Ltd., Airostyle
Plants 169
" 104 & 105. Airostyle Plant at Messrs J. Lucas, Ltd. 173
" 106. " " View of Racks and Fan 175
" 107. " " Two Bays of one Unit 181
" 108. Airostyle Plant installed for The Gas Light and Coke
Co., Ltd. 181
" 109. Airostyle Plant installed for The Gas Light and Coke
Co., Ltd. 185
" 110. Operator at Work 193
" 111. Airostyle Plant showing Ventilator 199
" 112. Elevation of Spraying Plant 199
" 113. Elevation of Spraying Plant 200
" 114. Plans of Figs. 112 and 113 200
" 115. Designs for Lamp Shades 203
" 116. Show Card done by Spraying 209
" 117. Another Example 209
" 118. Shaded Effects 213
" 119. Fruit Dish decorated by Spraying 217
" 120. Table Cover 219
" 121. Trough Tank 222
" 122. Floco System of Painting Motor Bodies 224
" 123 & 124. Show Card done by Spraying 225 & 229
" 125. Design for Show Card 233
" 126. The Perkins' Stove 236
" 127. Typical Goodyear Stove 237
" 128. Dipping Trough 238
" 129. Show or Menu Card 239
" 130. Example of Metal Decoration 241
" 131 & 132. Whitewash Sprayer 244
" 133 & 134. Limewashing with Bamboo Pole 245
" 135. The Brown Extension Sprayer 246
" 136. The Merryweather Limewhite Sprayer 247
" 137. A Tumbling Barrel 248
" 138. Another Form 248
" 139. Paint Sprayer for Freight Cars 252
" 140. Elevation of above 253
" 141. Details of above 254
" 142. The Metal Spraying "Pistol" 256
" 143. The Metal Sprayer 257
" 144. Sectional Drawing of Metal Sprayer 258
" 145. Diagrammatric Representation of Melting and
Spraying Jets in Action 259
" 146. Sprayed Decorative Work 261
" 147. Shaded Work by the Aerograph 263
" 148. Show Card, Sprayed 265
" 149. Sprayed Frieze 267
CHAPTER I.
INTRODUCTION.
Until recent years, it appears to have been generally supposed that
paint used for either the protection or ornamentation of various
surfaces must necessarily be applied by means of painters' brushes
made of hog's bristles. But it has been clearly demonstrated during
the past few years that the application of the paint may be made by
means of either total immersion of the article to be painted in a tank
or by spraying the paint on to the surface with the aid of compressed
air. The rapid increase in the use of both processes is principally
due to the immense saving of time which is effected, and this may be
approximately estimated at from five to nine-tenths. In other words,
one man can do the work of from five to ten men, or even more. To put
it another way, if a piece of work costs 20s. for labour in painting
by the old process, it may be safely assumed that it can be done by
dipping or spraying at a cost of from two to four shillings.
The question will at once suggest itself: "Is paint applied by dipping
and spraying as durable as that applied by the brush?" As the paint
in the greater part of work of this character is used solely for
protective purposes, the question is clearly one of considerable
importance. The answer to the question is that when properly prepared
paint is used, both methods give an equal, or even better result from
the point of view of durability than that which would be obtained if
a painter's brush was employed, while, in the case of painting by
immersion or by spraying, the paint finds its way into places which a
brush could not reach, such as open joints of a waggon, the intricate
parts of certain agricultural machinery, the inside of small metal
boxes, etc.
Both methods are successfully employed in practically every branch
of the engineering, metal and many other trades. Heavy steel sheets
may be dipped provided that adequate plant is employed for lowering
and raising them into the tank, or they may be sprayed without much
difficulty. Children's toys (to take the other extreme), costing
less than a penny each, may also be economically painted by dipping.
Speaking generally, anything large or small which can be handled or
moved by lifting machinery or on a turn table, can be painted by either
one process or the other. For example, a hundred or so of very small
iron castings, or wrought iron ware, may be placed in a wire basket and
dipped together in a few seconds, or the body of a motor car, or parts
of a bicycle, can be painted by spraying in a fraction of the time it
would take to do the work by means of brushes.
Thus far the processes are not much used in house painting, excepting
for the first or priming coat, before the work is fixed in position,
but certain types of the simpler form of spraying machines are employed
with great advantage in applying lime white or whitewash to rough
walls of factories, etc. In this case, a far better job is produced
in one-tenth of the time. The whitewash, when sprayed on, enters and
covers the open joints and inequalities of surface in a complete
manner, which would be impossible were a brush used.
On the next page is a list of some of the principal purposes for which
these methods are at present used, and these are being constantly added
to. It is not too much to say that in any industry in which paints
are used, one or other of the methods, or both in conjunction, may be
employed with very great advantage in a saving of time.
An erroneous idea prevails in some quarters that to install a paint
dipping or a paint spraying plant will involve a considerable
expenditure. As a matter of fact, if the work is of a simple character,
and the articles to be dealt with small, an expenditure of something
like £25 will be sufficient for the purpose. For example, a small tank,
with a draining board attached, would cost less than the sum mentioned,
even when the overhanging plant was included. As such work is usually
done in engineering shops, the lifting apparatus and the rails, can
easily be made on the premises. In some cases the lifting plant even
might be dispensed with, and the articles, such as paint cans, could be
dipped by hand. A spraying plant need not be expensive, and £25 to £40
will cover the expense of spraying apparatus, compressor for air spray,
exhaust and everything else. This, however, refers to a small plant.
More extensive installations would, of course, cost very much more,
but whatever they may cost, it may be accepted as a fact that, within
reasonable limits, the outlay will be fully returned in two or three
years' working at most.
In the following pages an attempt has been made to cover the whole
subject of painting by mechanical means. Many plants are described and
illustrated, and some lengthy explanation is given of the requirements
of different trades or goods. In many cases these have really nothing
to do with the painting proper, but success depends upon the system
adopted for handling and conveying.
Take, for example, celluloid buttons, which are usually sprayed. They
are placed in wire trays made specially for the purpose, the bottom
side uppermost. These are first sprayed all over with a spirit paint,
and when sufficiently dry to handle, say, in a quarter of an hour, they
are all turned over and the top sides are sprayed. The wire trays and a
handy cabinet to contain them are the important details in this case.
LIST OF THE PRINCIPAL PRODUCTS TO WHICH PAINT
SPRAYING AND PAINT DIPPING ARE APPLIED.
Acetylene Machines.
Adding Machines.
Addressing Machines.
Advertising Novelties.
Advertising Signs.
Aeroplane Work.
"Agate" Hollow Ware.
Agricultural Implements.
Air Compressors.
Aluminium Goods.
Antiques, Bric-a-brac.
Architectural Brass Works.
Architectural Iron Works.
Art Glasses and Mirrors.
Artificial Flowers.
Artificial Jewellery.
Artificial Marble.
Artificial Limbs.
Artistic Statuaries.
Automatic Vending Machines.
Automobile Lamps.
Automobile Licences and Number Plates.
Automobile Parts.
Automobile Parts and Motor Bodies.
Automobile Supplies
Automobile Tyres.
Automobile Tops and Canopies.
Axes.
Baby Carriages.
Badges.
Banners and Flags.
Bar Fixtures.
Barber Equipment.
Barrels.
Barrows.
Basket and Rattan Ware.
Bath Room Sundries.
Baths.
Bed Springs.
Bedsteads (Iron).
Bedsteads (Sheet Metal).
Beer Pumps.
Bells.
Bicycles.
Billiard Tables.
Bird Cages.
Blocks and Falls.
Blowers.
Boats.
Bobbins and Spools.
Boiler Work.
Book Cases.
Boxes, Cigar.
Bowling Alleys.
Boxes, Mail.
Brass Bedsteads.
Brass Goods.
Broom Heads and Handles.
Brushes.
Buckles and Snaps.
Builders' Hardware.
Burial Caskets.
Buttons (metal).
Cabinet Hardware.
Cabinets.
Cameras.
Candies and Confectionery.
Canners, Vegetables and Fruit.
Canoes.
Cans.
Cars.
Carpets.
Carpet Sweepers.
Carriages.
Carriage Hardware.
Casements (metal).
Cartridges.
Cash Registers.
Cash Carriers.
Celluloid Sheets.
Chairs (metal).
Children's Carriages.
China and Crockery.
Church and Lodge Goods.
Church and School Furniture.
Churns.
Clocks.
Colour Specimens.
Constructional Ironwork.
Corset Steels.
Coffins and Caskets.
Couches.
Cream Separators.
Curtain Poles.
Cutlery.
Cycles.
Cycle parts.
Desks (metal).
Display Fixtures.
Dolls.
Doors.
Drills.
Dynamos.
Edge Tools.
Electric Fixtures.
Electrical Apparatus.
Electrical Supplies.
Electro Platers.
Enamelled Metal Goods.
Enamelled Ware.
Engines.
Etching (metal).
Factory Fittings.
Fancy Baskets.
Fans.
Fenders.
Filing Cabinets.
Firearms.
Fire Extinguishers.
Fishing Rods.
Fixtures, Display.
Foundries.
Fountains, Soda.
Furniture (metal).
Garden Implements.
Gas Apparatus.
Gas Cookers.
Gas Engines.
Gas Fires.
Gas Fixtures.
Gas Meters.
Gas and Gasolene Stoves
Golf Clubs.
Grates and Mantels.
Gramophones.
Grille Work.
Hats, Straw.
Hair Pins.
Hames.
Handles.
Harness Trim.
Harrows.
Hardware.
Hollow Ware.
Hooks and Eyes.
Horns.
Incandescent Lamps.
Japanned Goods.
Jewellery.
Kegs and Pails.
Kitchen Cabinets.
Kitchen Utensils.
Knitting Machines.
Lacing Studs.
Lamps and Lanterns.
Lasts.
Lawn Mowers.
Lead Pencils.
Leather Work.
Letter Files.
Locks.
Lockers (metal).
Looms.
Locomotives.
Machinery.
Malleable Castings.
Mathematical Instruments.
Meat Safes.
Metal Spinners.
Model Makers.
Motors.
Motor Cycles.
Musical Instruments.
Novelties.
Office Furniture.
Optical Instruments.
Ornamental Ironwork.
Pattern Makers.
Pen Holders.
Phonographs.
Physical Supplies.
Piano Plates.
Pianos and Organs.
Picture Frames.
Pins.
Plated Ware.
Ploughs.
Plumbers' Supplies.
Porcelain Goods.
Projectiles.
Pulleys (metal).
Pumps.
Radiators (auto).
Railway Carriages.
Rakes.
Refrigerators.
Regalia.
Rubber Goods.
Rules and Levels.
Saddlery Hardware.
Safes.
Safe Deposit Vaults.
Sashes (metal).
Scales.
Screens (metal).
Sewing Machines.
Shoe Buttons.
Show Cases.
Side Cars.
Signs, Enamelled.
Silverware.
Sleds and Sleighs.
Soda Fountains.
Sporting Goods.
Steel Stampings.
Stoves (gas).
Slate, Enamelled.
Statuary.
Steam Gauges.
Steel Castings.
Street Railway Companies.
Surgical Supplies.
Switchboards.
Tables.
Tanks.
Telephones.
Telephone Supplies.
Textile Machinery.
Tinwares.
Thermometers.
Tools.
Toys.
Trunk Hardware.
Typewriters.
Vacuum Cleaners.
Vending Machines.
Veneers.
Ventilators.
Wagons.
Wall Papers.
Washing Machines.
Watering Cans.
Weighing Machines.
Wheels.
Willow Ware.
Wire Cloth.
Wire Mattresses.
Wire Work.
Wringers.
In addition to the above, paint is applied by spraying for many
artistic purposes, such as for show cards, photographic work,
lithography, church decoration, etc. These are referred to in another
chapter.
[Illustration]
CHAPTER II.
PAINTING BY IMMERSION.
The process of painting various articles by dipping them bodily into
specially prepared paint contained in a tank or other receptacle is a
very old idea. It has, however, developed considerably in late years,
and is now largely employed in many industries, particularly in the
finishing of agricultural implements of various kinds, iron work and
a hundred and one other articles. It is sometimes used in conjunction
with paint spraying; that is to say, the first coat or coats may be put
on by immersing the article to be painted in the paint, or varnish, and
the final coat of enamel or varnish may be put on by means of a spray.
In some cases, the final coat is applied by means of brushes in the
ordinary manner.
Perhaps the simplest form of paint dipping is that applied to various
articles, such as bolts, rings and small parts, which are placed in a
wire basket and plunged into the paint. The basket is then hung up for
a quarter of an hour or so to drain, and afterwards in another place,
until such time as the paint becomes hard.
Another familiar example of painting by dipping is that of ordinary
tapered cans, such as those which are used to contain varnish, etc.
In this case, a piece of wood is introduced into the neck, the can is
immersed in the paint up to almost the top of the neck, and is then
placed upside down to drain and to dry. A paint which dries with a
gloss is usually employed for this purpose, and it may be remarked that
a good deal of this work is now done by spraying; in fact, a great deal
of difference of opinion exists as to the respective merits of the two
processes for this particular purpose.
[Illustration: Fig 1.--CROSS SECTION THROUGH PAINT TANK.]
Going a step farther, we come to the consideration of articles such
as iron sashes and casements, parts of staircases, etc., which may be
dipped into a tank containing, say, five to ten gallons or so. Such
tanks are usually made to slant at the bottom in order to facilitate
cleaning when necessary. Adjacent to them is provided a platform,
usually lined with sheet iron upon which the paint can drip after the
articles are removed from the tank, and a system of overhead rails for
moving the articles from one part of the works to another. No agitating
apparatus for the paint is required, but after the tank has been used
for some time, say, for example, at the week-end, it is necessary to
stir it up by means of a pole before the work commences. As a matter of
fact, the articles being plunged in the tank, and their withdrawal, in
itself stirs the paint sufficiently for the purpose.
In dealing with the larger-sized articles which are to be painted,
such as reaping machines, the construction of the tank which may hold
several tons of paint is naturally of a more elaborate character. Such
a plant will consist, first, of the tank itself; next, the system of
overhead railing; third, the apparatus upon which the articles to be
painted are hung; and fourth, the hoists for lowering and raising such
articles into and from the tank. It will be convenient to consider
these parts which go to form a complete installation under their
several heads, taking a more elaborate plant by way of example, it
being understood that the plant may be simpler in form when the size of
the articles to be painted is small, or under other circumstances, such
as will be presently suggested.
THE TANK.
[Illustration: STIRRERS AND BLINDS FOR PAINT DIPPING TANK. Fig
2.--PLAN. Fig. 3.--LONGITUDINAL VERTICAL SECTION.]
There are two forms of special tanks in general use, one having at the
bottom paddles for agitating purposes, and the other worms provided
with the same object. Fig. 1. shows a cross section of a tank made on
the McLennan patented system. In this two series of paddles revolving
in opposite directions are provided, and above them is an appliance
which may be likened to a horizontal venetian blind, consisting of iron
laths, which are nearly horizontal when closed, forming a platform
upon which the paint can settle, and vertical when open. This blind
is left open when the tank is in use, and is closed when it is at
rest. The illustration gives the dimensions of the parts, although
these, of course, will be varied according to circumstances. Above the
blind is sometimes a grating, which, together with the blind, form a
protection to the agitating gear from articles dropped into the tank by
mistake, the two together preventing the heavy, pigment in the paint
from clogging the paddles when the agitating gear has been stopped
for some time. Figs. 2 and 3 show respectively longitudinal plan and
section, from which the construction will be clear.
Messrs. Wilkinson, Heywood & Clark, Ltd., of Poplar, who own the
McLennan patents, in a little book, entitled "Painting by Immersion,"
state that there were certain disadvantages in the design of this
tank, inasmuch as should it become necessary to remove or repair the
paddles, it would be necessary to empty the tank and bodily remove the
parts. They have, therefore, a new design, which is shown in Fig. 4,
in which this remedy is overcome. The agitating gear, in this case,
is on a sub-frame, separate and independent from the tank itself. The
drive is in the tank, and is taken by means of a claw clutch through
a right angled bevel to the agitating shaft. This design has proved
very satisfactory for small tanks. For very large tanks a gear is
recommended in which the agitating gear is enlarged and the shafting
is supported or stiffened to prevent whipping. This entails a design
of some special bearing, which should be paint proof and oil proof,
for the reason that the bearing is immersed in the paint itself. In
Fig. 5 is shown drawings of this bearing, on which the firm named hold
patents. The perfected plants now consist of a tank with an independent
and removable chassis frame, on which are mounted the Venetian blind
arrangements, already mentioned, together with the agitating gear,
which consists of either one, two, or more parallel shafts, mounted on
parallel gear, as shown in Fig. 6.
These shafts are held on the sub-frame with the patent bearings already
referred to, and the drive is transmitted through the bevel gear
encased in a special gear box, which is equally oil and paint proof
and self-lubricating. It will readily be seen that with this plant it
is an easy matter to withdraw the driving gear and lift the sub-frame
bodily out, without in any way disturbing the paint in the tank. The
tank, therefore, can be buried nearly flush in the ground, embedded in
concrete, and need never be disturbed. In case of emergency, and when
painting is continuous throughout the year, it is recommended that the
consumer should keep a complete spare chassis for use when occasion
requires.
[Illustration: Fig. 4.--DESIGN FOR TANK FOR PAINTING STEEL SHEETS.]
[Illustration: Fig. 5.--DETAILS OF PAINT-PROOF BEARINGS AND GEAR BOX.]
[Illustration: Fig. 6.--DETAILS OF SUB-FRAME, SHAFTING AND DRIVING GEAR
FOR TANK DESIGNED FOR IMPLEMENT MANUFACTURERS.]
Whatever the construction of the tank itself may be, and whether or not
it is provided with agitating apparatus, it is generally found most
convenient to build it with the top nearly level with the floor. It is
advisable to provide iron doors or covers to close the tank in when
out of use so as to prevent excessive evaporation and also for use
in case of fire. These doors or covers should therefore be actuated
by levers or other suitable appliance which may be put in motion at
a point some distance from the tank itself, for while the paint is
not very liable to catch light, an accident may cause it to do so,
particularly when electricity is used in the works, and the closing of
properly constructed doors will quickly subdue fire as far as the tank
itself is concerned by shutting off access of the air. The usual plan
followed is to provide wide strips of thick felt attached to the doors
in proper position so that when the doors are closed the contact will
be thorough and the tank itself be practically sealed.
When agitators form part of the apparatus it is not necessary to buy
the paint ready mixed for use, as it may be introduced into the tank
in thin paste form; the necessary thinners such as white spirit can be
added and the agitating apparatus slowly revolving will quickly mix the
parts together and render the paint suitable for use.
It will be understood that the form of tank above described may be very
considerably modified according to circumstances. In very simple paint
dipping, such as is required for small articles, casements, etc., the
agitating apparatus may be wholly dispensed with, while in other cases,
the shutter-like arrangement above mentioned may be omitted and the
agitator may consist of a worm with a screen above to protect the parts
from pieces which may accidentally fall in.
[Illustration: Fig. 7.--GENERAL LAY-OUT OF A THREE-TANK PLANT DESIGNED
FOR THE USE OF AN AGRICULTURAL IMPLEMENT MAKER, USING THREE COLOURS IN
THIS INSTANCE, RED, GREEN AND BLUE.]
THE RAILS AND HANGING APPARATUS.
[Illustration: CROSS SECTION. SIDE ELEVATION. Fig. 8.--JOIST AND WHEELS
SUPPORTING HANGER.]
These two details may be conveniently considered together, and it
should be stated at once here again a great deal of difference of
opinion exists as to what system is the best. It should, however, be
clearly understood that upon the system of railing a great deal of
the success depends. The object, of course, to be attained is that of
handling a large number of parts with as little labour as possible.
With this object, a complete system of overhead rails, commencing
with the finishing shops, leading to the paint tank, and thence to
storage or delivery departments, should be carefully thought out,
always remembering that the growth of a business may necessitate the
erection of additional buildings from time to time and provision made
accordingly. One of the simplest and best forms of rails is an H
section joist with two wheels on either side as shown in Fig. 8. In
other cases an =L= rolled joist is used, the railing part being on the
vertical flange while the horizontal flange is connected with rods
fixed to the upper part of the building. One method which is used quite
successfully is to employ hooks as shown in Fig. 9. These run over
rails which are lubricated with vaseline, and in this case the rails
are usually slightly inclined. In very large works, however, where
a considerable length of rail is employed this inclination might be
inconvenient, as the rails would go too near the ground. In all cases
horizontal rails are found in practice to be the most convenient, but
an installation requires careful consideration from all points of view
and no general rules can be laid down.
HANGING AFTER DIPPING OR SPRAYING.
A practical point of more importance than might be supposed, at first
sight, is to avoid hanging articles very close together after they have
been painted or enamelled, either by dipping or spraying. The reason is
that if they are hung quite close together the turpentine or volatile
thinner used in the paint may affect part of the adjacent surface, and
cause a diminished gloss.
[Illustration: Fig. 9.--HOOK FOR HANGING.]
This point was brought to light in the case of one manufacturer who was
painting varnish cans by dipping. They were hung up to dry quite close
together--in fact, almost touching. When dry, it was noticed that,
instead of being nice and glossy all over, one side was somewhat dull.
The explanation appeared to be that the turpentine fumes affected the
paint in drying, and this was proved to be true, as when the cans were
placed farther apart the trouble ceased.
HOISTS.
The hoists used will depend upon the size and weight of the objects
that are to be dipped. In some cases they may be dispensed with
altogether and the dipping can be done by hand.
[Illustration: Fig. 10.]
[Illustration: Fig. 11.]
[Illustration: Fig. 12.]
[Illustration: Fig. 13.]
[Illustration: Fig. 14.]
[Illustration: Fig. 15.--A TYPICAL HOIST FOR USE IN PAINTING BY
IMMERSION.]
In cases where the space is confined, it is sometimes desirable to use
hoists in the form of wall crabs, and a few of these made by the London
Hoist Machinery Co., Ltd., 103, Worship Street, E.C., are illustrated
in Figs. 10 to 14. The hoist shown in Fig. 10 will lift 10 cwt. with
slow speed on the left-hand side, and 3 cwt. on the right-hand side
with a quick speed of 13 feet per minute. This form can be made
lower by brake if desired. The little crab shown in Fig. 11 deals with
weights of 1 cwt. at a speed of 60 feet per minute, while that shown in
Fig. 12 is also a quick gear, lifting 3 cwt. at 13 feet per minute. The
other illustrations are self-explanatory.
Fig. 15 shows a typical hoist which may be regarded as an ideal
installation for the work, and the idea can be adapted to either
large or small works as required. The installation consists of an
overhead track with a movable portion over the dipping tank. The goods
to be dipped are hung on the trolleys and run one by one on to the
movable portion of the track over the tank. There is a stop on this
portion to prevent the trolley running right over the tank, and the
movable portion with the article to be dipped is lowered into the
tank, and afterwards raised by means of a hoist. The hoist in this
case was driven by pneumatic power. It could, however, in very small
installations be a hand hoist worked by the rotary movement of a
handle, or in other large installations a quick moving electric hoist.
After the article is dipped and the movable portion raised by the hoist
to its correct position in the track of the runway, the trolley is run
off the movable portion on to the track beyond the tank, and left there
to dry.
These overhead runways can be made to suit loads from 2½ cwts. up
to 10 tons, so that the system covers all classes of work, since it is
seldom that it would be necessary to dip articles weighing more than 10
tons.
Fig. 16 shows a Morris standard electric trolley hoist suitable for
lifting up to, say, 5 or 6 tons. Both of the foregoing hoists are made
by Messrs. Herbert Morris, Ltd., of Loughborough, to whom the author is
indebted for these illustrations.
In Fig. 17 is shown another type of trolley hoist suitable for lifting
heavy weights.
THE NUMBER OF COATS OF PAINT TO BE GIVEN.
An important consideration both in paint immersion and paint spraying
is the number of coats of paint which should be given in order to
produce the required appearance and ensure durability. This must
necessarily depend upon the use to which the article to be painted
is to be put, and it will also depend upon the appearance. In paint
spraying it is clear that any thickness of paint required could be
obtained by continuing the operation of spraying, but it has been found
in practice that it is not desirable to continue the application of
the paint beyond the point when every part of the surface is completely
covered. It is a well-known fact that three thin coats of paint applied
separately will prove more durable than two thick coats, even if the
quantity of paint used in the two cases is identical. The same is true
to a great extent when the paint is sprayed on. When it is applied by
dipping another important element enters into consideration, and that
is, thin coats are a practical necessity, because if an attempt was
made to make the coat thick it would inevitably result in unsightly
runs, fat edges, etc., which would wholly spoil the work. Where the
object is only that of a temporary protection, as in the case of iron
castings, a single coat will usually suffice, because the castings when
fixed in position will be painted with the building in the ordinary way.
Sometimes a priming or first coat of paint is given by dipping, and the
following coats are applied by brushes or by spraying. There appears
to be some idea that when paint is applied by brushes it is forced
into the pores of the wood and therefore holds better; as a matter of
fact, in a well-designed paint the thinners will penetrate the wood
and no particular force is necessary; but if it should be, it will be
certainly supplied by the spraying process.
ADVANTAGES OF THE DIPPING PROCESS.
The advantages of applying paint, japan, enamel, or varnish by the
process of immersion are obvious. The saving of time is the chief
advantage, and this will be in most cases very considerable. For
instance, a complete wagon can be painted by dipping in a very few
minutes, while large and intricate agricultural machines may be painted
in the same way in a fifth part of the time it would take to spray
them, and probably a twentieth part of the time it would take to do the
work by hand.
There is another advantage which should be mentioned when paint dipping
is compared with spraying. In the latter, an outfit consisting of
sprayer, air compressor, exhaust, cabinet, etc., are all necessary. In
dipping, however, the apparatus may in many cases be of the simplest
character. For example, in painting bedsteads all that is necessary is
a narrow but deep tank containing the paint, into which the bedstead
may be plunged by hand and then hung up to drip over a metal-lined
floor.
[Illustration: Fig. 16.--A MORRIS STANDARD ELECTRIC TROLLEY HOIST.]
In Birmingham, hundreds of iron bedsteads are dipped in this way every
day. The head or foot of the bedstead is taken in the two hands of the
operator, dipped into a tank of black japan, and immediately hung up
on a travelling chair, which slowly carries it across the room to the
oven, the superfluous paint dripping off during the process.
In another chapter will be found the advantages which the process of
spraying has over dipping. A decision as to which is the best system
to adopt for any particular purpose can only be determined after due
consideration has been given to all the circumstances bearing upon the
work to be done.
It may be pointed out in this connection that the process of painting
called "flowing on," which is fully described on another page, is in
effect only a modification of dipping. As a motor body, for instance,
cannot be plunged into a paint tank because the inside is not to be
painted, the paint is literally poured over the surface, and the effect
is exactly the same.
PROTECTING PARTS NOT TO BE PAINTED.
It frequently happens in paint dipping that certain parts of a machine
or other article that is desired to be coated with paint is to be left
unpainted, and the problem is how to effect this most economically. The
method usually employed is to cover the parts, such as name plates,
bright portions of a machine, etc. with vaseline. When the article is
dipped the paint covers this as well as the other parts, and after the
paint is dry the vaseline and the paint on it can be easily wiped off
and the surface beneath it will be found to be quite clean.
PREPARING WOODWORK BEFORE PAINTING.
Previous to the priming coat of paint being applied to any article made
of pine or other wood containing knots it is necessary to protect such
knots by applying one or two coats of a liquid known in the trade as
"knotting." If this were not done the rosin which exudes more or less
from the knots would penetrate the paint, discolour it and give a very
unsightly appearance.
The best knotting consists of shellac dissolved in alcohol, usually in
the form of methylated spirits; in other words, it is shellac spirit
varnish. Many inferior grades, however, are sold in which the shellac
is adulterated with rosin or other substances, while the alcohol is
sometimes replaced wholly or in part with naphtha. These inferior
qualities of knotting should never be used, as they are very likely
indeed to cause trouble and spoil the whole job.
Although the parts of machines such as agricultural implements are
usually made of selected and well-seasoned timber, it sometimes happens
that portions of the work are found to be more or less sappy. This
should also be coated with knotting, as otherwise they will absorb the
paint to too great an extent and the priming coat will not be uniform.
In passing, it may be observed that a coat of shellac varnish--a term,
as already explained, which is synonymous with knotting--is very useful
as an undercoat whenever there is an excess of rosin as in pitch pine.
It is also used to stop suction on plaster ornaments which are finished
in imitation bronze, and which may successfully be used over tar or tar
spots which it is desired to paint.
It is very important that knotting be applied in quite thin coats, and
it is for this reason that usually two coats are given. If it is too
thick it fails to dry properly. Thick knotting may be used if it be
well brushed out, but this is almost impossible in applying it to the
knots of ordinary woodwork which are merely "dabbed" with the end of
the brush; moreover, such work is usually done by piece work, hence two
coats are much safer to use.
FILLER FOR IRON.
It is sometimes necessary before dipping or spraying cast iron work to
fill up sand flaws and inequalities. This may be effectually done by
using a filler prepared as follows: Mix together equal parts of genuine
red lead and gilders' whiting and add two parts of boiled linseed oil
and one part of goldsize. It will be found most effective to mix the
two liquids last mentioned before adding them to the dry lead and
whiting. Thoroughly mix all together, or, preferably, grind through a
mill until the putty-like consistency is obtained. This stopping will
dry very hard. It is important to remember that this filler must be
mixed in small quantities as required as it rapidly becomes hard, so
that if a considerable quantity were made at one time any unused would
become spoiled.
[Illustration: Fig. 17.--ELECTRIC HOIST SUITABLE FOR HEAVY GOODS.]
Another recipe of an entirely different character for a cement or
putty for the same purpose is made by mixing one parts of flowers of
sulphur, two parts of sal-ammoniac and 80 parts of iron filings and
making them into a paste with water. By increasing the proportion of
sal-ammoniac the setting is also increased.
STOPPING HOLES IN WOODWORK.
However carefully a piece of woodwork may be prepared, there are
usually more or less depressions or holes such as those which occur
over countersunk nails, and in other places which require to be filled
up. The usual stopping for this purpose employed by house painters is
a mixture of equal parts of dry whiting and dry white lead, made in
the form of putty, with raw linseed oil to which, say, 10 per cent. of
boiled oil has been added. A cheaper and quite as effective a stopping,
however, can be made by using a material known as "Alabastine," which
possesses the advantage of being easily cut down. This material may be
also used when mixed to a thinner consistency for priming, but it is
not suitable for being applied by dipping, although it may be sprayed.
The very best stopping is one such as is used by carriage painters,
and is strongly recommended for high-class work. It is supplied both
in powder and paste form by all first-class varnish manufacturers,
and although the cost is a little higher than that of stopping putty
made of whiting and linseed oil, as described, it is well worth the
difference.
An excellent filling composition for coach and motor body builders,
railway and tramway carriage manufacturers, etc., is that made by the
well-known varnish house of Messrs. Wm. Harland & Son, Merton, S.W.
It is especially suitable, obtaining a perfectly level and unyielding
groundwork where a fine finish is to be given, either in paint, varnish
or enamel. It is made in two colours, grey for dark work and cream for
light colours or white, and costs sixpence a pound, or less when bought
in quantities.
It effects a great saving of time and labour, being already finely
ground into a stiff paste, which only needs the addition of specially
prepared thinners to bring it to a proper consistency for use with the
brush.
It is most successful and expeditious as well as the most economical
process for giving a smooth surface to rough castings--a condition
which is, of course, indispensable when these have to be painted and
varnished.
For ordinary surfaces of woodwork of a slightly rough or uneven
character, two or three coats of the filling composition will suffice
to produce, when carefully rubbed down, a perfectly smooth surface of
a hard metallic nature, combined with great tenacity and durability.
"Philorite" is another speciality which may be mentioned in this
connection. It is manufactured by Messrs. Wilkinson, Heywood and Clark,
Ltd., and is a filler made in white and seven colours. This is a great
advantage when the finish is to be coloured, as it may save a coat of
paint. It can be rubbed smooth without difficulty, and will serve as a
perfect ground for enamels and japans, as well as for paint. For use it
is thinned out with American turpentine to the required consistency,
say, that of a ready mixed paint. It is brushed on with a stiff bristle
brush, and two coats may be safely applied on one day. The last coat
can be rubbed down smooth with pumice and water or sandpaper. It may
also be used as a knifing paste for defective surfaces.
RUBBING DOWN.
In many cases the coats of paint, japan or enamel have to be rubbed
down between coats in order to produce a perfectly level surface.
This is usually done by means of finely powdered pumice stone and
water, and it is important to remember that the operation must be done
with care so that the rubbing is quite uniform. If a slight gloss is
given to the paint the portions which are rubbed down can readily be
discerned, as they will have a gloss, and in this way uniformity can
be ensured. It is of the utmost importance that all of the powder be
washed away before the next coat is applied; if any is left it will
mar the job. It may be noted that the work of rubbing down may be done
more expeditiously by means of the finest grade of steel wool. On the
Continent this is now used exclusively, and it is rapidly gaining
favour in Great Britain.
[Illustration: Fig. 18.--SPRAYED SHOW CARD.]
[Illustration: Fig. 19.--DIPPING AND STOVING BEDSTEADS.]
CHAPTER III.
REQUIREMENTS OF DIFFERENT TRADES.
The following are a few of the special requirements of different
trades as to paint dipping. The details might be lengthened almost
indefinitely.
BEDSTEADS.
The methods adopted for the class of work will, of course, depend upon
the quality of the finish required. Cheap bedsteads may be done by
dipping in one coat of black japan and stoving at 350° F. In better
class work several coats may be applied either by dipping or spraying,
and each may be rubbed down after stoving. If a good enamel is used
this is unnecessary.
When the work is white several coats--say, at least three--are
necessary, for white japans cannot be made which will cover
sufficiently in one coat. White lead should not be used in this class
of work for the reason that a good deal of handling of parts is
necessary, while the rubbing down is sometimes done with glass paper
and cause dust, both of which may give rise to lead poisoning. All of
the best white japans or enamels are made on a base of zinc oxide or
lithopone (zinc sulphide), or a mixture of them.
COLLAPSIBLE GATES.
This work is usually done by dipping in paint which dries "flat,"
i.e., without gloss. The colour is, as a rule, black. In fitting and
adjusting the work in order that the parts will collapse readily it
is necessary to apply a lubricating oil where the rods meet. This
lubricating oil is difficult to remove after the adjustment has been
completed, and therefore the last coat of paint is usually put on by
hand. It is suggested, however, that raw linseed oil might be used
instead of lubricating oil, and that this could be wiped off as soon
as possible after the adjustment. In such a case the paint could be
applied by dipping, as if even a little of the raw linseed oil were
not removed it would not interfere with the drying of the paint to any
material extent.
DIPPING SEWING MACHINE PARTS.
The process employed by a very large firm of American manufacturers is
as follows:--
When the castings come from the machine shop they are boiled for 20
minutes in ammonia water to kill the grease (1 of strong ammonia to 20
of water), and are then rinsed in hot water. Any holes or inequalities
in the castings are then stopped with a filler made from dry white
lead, mixed into a stiff paste with some varnish, brown japan dryers
and dry lampblack made quite stiff. When the stopping is hard the
castings are dipped into a black metallic coating thinned with 62%
benzine to a specific gravity 850. They are then dipped with two coats
of finishing japan (sp. gr. 830) flatted with powdered pumice after
each coat and leathered off. The parts which are not plated or flatted
are given 5 hours stoving at 325° F., and are then rubbed with pumice
and carpet pad until flat. Cut out gold transfers are then fixed with
transfer varnish and the work is stoved at 185° F. The parts are then
sponged and dusted, and are given a good coat of polishing varnish (sp.
gr. 950) Finally the work is rubbed down fine with glass paper and
pumice powder and then polished with machine oil and rottenstone powder
for the iron, or rottenstone and benzine for the tables. The latter, as
well as the covers for these, are not usually dipped but brush finished.
IRON RODS.
[Illustration: Fig. 20.--IMMERSING MANGLE FRAMES.]
In most cases, iron and steel rods are best painted by immersion, as
the small surface presented would cause too much waste if spraying
were attempted. As in most cases of dipping, success depends largely
upon the means adopted for handling and dipping a number of rods at
one time. Frequently, stoving is required to harden the japan, because
a rod is often subjected to considerable wear. Perhaps the best plan
to adopt, where the number of rods to be treated warrants the outlay,
is to provide mechanism by which the rods are dipped and are at
once automatically carried into a stove, and by means of slowly
travelling chains, carried out at the other end.
An excellent contrivance for the purpose is in use at the Ford Motor
Works, at Manchester. This consists of a vertical oven, heated by gas,
and having slowly-moving endless chains running from bottom to top and
down again to a point where the rods are discharged on to inclined
runners. These rods are passed through a bath of japan, are then taken
up by the chain, and, during their progress, are baked. A gear is
provided by which the time between the entry of a rod to its discharge
may be varied from twenty to ninety minutes, or any period between,
according to the purpose for which the rod is to be used and the degree
of hardness of the japan required.
IRON WINDOW FRAMES OR CASEMENTS.
A long narrow tank, say, from 1 foot 6 inches to 2 feet wide and 15
feet long, is suitable for this class of work, which is usually done in
one coat only, and this is quite sufficient to protect the iron until
the casement is fixed in position, when it will, of course, receive
additional coats by means of a brush in the ordinary way.
It is important that the iron be dipped just as soon as it leaves the
finishing shop, and it is necessary that the surface be thoroughly
cleaned before the paint is applied, and particularly after all scale
is removed. Sometimes the application of the sand blast is necessary
for this work, but, as a rule, a vigorous application of suitable wire
brushes will suffice.
Another very important provision is a system of overhanging rails on
which the sashes or other articles can be run direct from the finishing
shop to the paint tank, and thence to any part of the building, from
which they may be taken as required for shipment.
The paint used for casements is usually grey, being as a rule made of
zinc oxide and lampblack. These pigments, when mixed with a suitable
vehicle, are very durable, while, the colour being neutral, it is
suitable as an undercoat for green, as well as nearly any other colour
which it may be desired to use as a finish. The weight of the paint
should be 13 lbs. to the gallon, and it should dry with a semi-gloss.
The elevating apparatus need only be of a simple character, and several
casements can be suspended and dipped at one time. For this purpose
a "hanger" is used, having perforations through which one end of the
hooks pass. One form is shown in Fig. 21. By the side of the tank
should be a large metal lined floor, say, 20 feet by 15 feet, or even
larger, inclined toward the tank. The frames having been plunged into
the paint, are at once withdrawn and hung in rows to dry over this
floor. The superfluous paint drips on to it and runs back through a
screen or sieve into the tank. The latter should be provided with a
cover, to be closed in when the work is not being proceeded with.
[Illustration: Fig. 21.--IRON HANGER FOR SUSPENDING SEVERAL ARTICLES TO
BE DIPPED TOGETHER.]
In this class of work it is unnecessary to employ a stirring apparatus
provided that the paint is of the right consistency, and an occasional
stirring up with a pole after the work has been suspended, say, for
example, from Saturday to Monday, will usually be all that is required.
As a matter of fact, the lowering and raising of the casements into the
paint effectually stirs it up.
METAL FURNITURE.
[Illustration: Fig. 22.--THE AUTOMATIC FINISHING OF PIANOS. CARRIER
FILLED WITH SIX COMPLETE PIANOS.]
Under this head it is intended to include such articles as deed boxes,
lockers, files and other metal goods which are required to be painted
both inside and out. An enamel stoving or baking paint is usually
employed for the purpose, while the tank must be of sufficient size to
accommodate the various articles that are to go into it. Taking a deed
box by way of example, a large iron hook, such as is shown in Fig. 32
is placed inside the box so that it is suspended at an angle; the box
or boxes are then lowered into the tank and immediately withdrawn after
all the superfluous paint runs away, care being taken that the box
hangs at a proper angle to permit of this being done. Great care must
be taken in this room to exclude all dust, which would considerably
mar the work. For this purpose wire netting of the finest mesh should
be placed over the windows so as to screen off any dust which might
otherwise enter. A system of overhead rails are made, consisting
of an L-iron on the top side of which run two rollers to which are
attached hanging gears, and is sufficient for the purpose. At
least ten minutes should be allowed for these articles to drip over
the inclined floor adjacent to the tank, and for safety's sake it is
as well to employ a workman with a brush in his hand to go over each
piece and remove any tears or runs which may possibly occur. Metal
work of the description named is then placed in a stove and baked for
three hours at a temperature of 400° F. The paint is frequently green,
which is found to be a good serviceable colour and which is attractive
in appearance. After the baking the paint is quite hard, and will
withstand more or less rough usage. If any ornamental work is required,
this is done afterwards, as explained under the head of "Stencilling."
The paint employed weighs 13 lbs. to the gallon, and a fine mesh
paint strainer must be provided, through which the superfluous paint
passes as it drips from the articles on their way to the tank. In
this case, as in others, no special stirring apparatus is required,
as the comparatively heavy vehicle and the relatively light specific
gravity of the pigment employed gives little or no opportunity for any
"settling out."
MOTOR PARTS (METAL).
The various parts which go to make up a complete motor car are
differently treated according to their shape and size. In most cases,
stoving is resorted to, because the enamel or japan is thereby
much increased in durability by the hardening which takes place in
consequence of the high temperature.
The steel rims of wheels are dipped by hand into a black japan made
especially for the purpose. They are hung on hooks and allowed to drain
for some minutes, and are then transferred to the stove, where they
are subjected to a heat of 320° F. Such parts as ribs, front and rear
wings, running boards, shields, etc., are dealt with in the same way.
Previous to dipping, these parts undergo the process known as
"pickling," by which scale, grease, etc., is removed so that a
perfectly clean surface is presented to receive the japan.
Troughs to catch the drips must be provided, and it is essential that
these be kept quite clean, so that the superfluous japan may run
through gauze and be pumped back again into the tank to be used again.
AUTOMATIC FINISHING OF PIANOS.
THE STANDARD HYDRAULIC IMMERSION SYSTEM.
Any doubt as to the perfection of finish which may be produced by a
carefully thought out system of immersion or dipping must be removed by
the fact that such a system has been in successful use for some years
for the finish of pianos. It need hardly be pointed out that such a
finish must necessarily be so well done as to approach perfection.
One firm has made a special study of this subject, viz., the Standard
Varnish Co., of London and New York, and their efforts have been most
successful.
By this method an absolutely even distribution of varnish is always
secured; no part of the piano case is neglected and an enormous
reduction in the cost of varnishing is effected. The factory output can
be readily increased as desired, as the varnish working force of the
factory can do as much or as little work as trade conditions may demand.
The mechanical details have been so perfected that every kind of
instrument can be handled satisfactorily.
The excellence of the finishing done in accordance with this system
is attributable to a large extent to its mechanical construction.
The apparatus used in connection with the Standard method of piano
finishing consists, in the first place, of a steel tank for the varnish
with an adjustable cover which can be locked when the apparatus is
not in operation, a hydraulic lift for raising the work slowly out
of the varnish, a small horse-power pump which is operated either by
steam pressure or compressed air, and in extreme emergencies where the
pressure is not adequate for heavy work, a small motor for operating
the pump.
There is also installed an apparatus similar to the automatic sprinkler
system. A fusible link or another mechanical device makes it possible
to draw off the varnish into a tank outside the main buildings at will,
and for protection in case a fire should take place in any other part
of the building.
The principal investment for the piano manufacturer is the carriers or
racks for holding the separate pieces. The cases are held firmly in the
carriers by means of springs which are adjusted for the introductory
carrier, or secured by screws in the permanent carrier which is
designed for keeping the cases in the carrier until they are ready for
rubbing. This latter method saves the labour of handling.
[Illustration: Fig. 23.--AUTOMATIC FINISHING OF PIANOS. INTRODUCTORY
CARRIER READY FOR PARTS TO BE VARNISHED.]
Carriers filled with work to be varnished are raised from the floor,
swung directly over the tank, and lowered into the varnish by means of
an hydraulic lift. The speed with which the work is raised from the
varnish is controlled by a lever conveniently located for the operator.
Once the speed has been determined and the lever set the apparatus
requires merely the supervision of an operator, who may devote
considerable time to helping his assistants reload another carrier
while the one in the tank is emerging. Generally only a limited number
of carriers are required.
When the work is to be removed between coats a large percentage can be
handled without tack in a short time after it is taken from the varnish.
In the introductory carrier, parts like piano tops, which are finished
on all sides, require a little additional care because of the
difficulty of handling. This contingency is provided for by the use of
special head pieces.
In emergencies, for rushing out an extra quantity of work, carriers
holding falls, frames and small parts may be immersed in one-half the
interval usually required.
For example, these carriers can be withdrawn in from fifteen to twenty
minutes, whereas for carriers including sides from twenty-five to
thirty minutes are required. The carriers are equipped with head pieces
adjustable to meet all peculiar local factory requirements. In fact,
these carriers can be constructed by the manufacturer to meet all his
demands.
The number of carriers necessary depends entirely upon the volume of
work to be handled. But it is desirable, when possible, to have a
sufficient number of carriers to hold all the work until the varnish is
sufficiently dry for rubbing. In this way a tremendous amount of labour
and time is saved.
Permanent carriers, in which the work has been secured by ordinary
screws, have been constructed by some manufacturers at an unusually low
cost by their own machinists in their own factories.
The work in the carriers can be easily dusted by means of air-bellows
or a compressed air-blower. Work finished in this manner is so clean
that the usual sanding is not necessary and a considerable amount of
labour thereby saved.
That the Standard hydraulic immersion system of automatic finishing
of pianos has distinct advantages over the ordinary hand process is
obvious even to the casual observer. Among the numerous advantages
which have been effected the following seem to be worthy of special
consideration:
It constitutes practically the factory's entire varnishing force.
Its use insures an even coat, free from imperfections.
Coating both sides of the work preserves the cases considerably from
shrinking and warping. A great deal of labour is saved by varnishing
both sides at once.
It requires very little more varnish than the old, slow, hand method
as there is no waste from brushes and pots and absolutely no dripping
outside the tank.
The elasticity of the Standard system of piano varnishing eliminates
the necessity of additions and reductions to the working force.
The cleanness and evenness of the finish virtually makes every coat a
flowing coat. The amount of time and effort saved in the rubbing and
polishing is tremendous, and the finish obtained is much finer, due to
the absence of uneven coating and the blemishes of pinholing and dust.
Carriers containing six complete pianos each, at an average interval of
one half-hour, will enable the factory to turn out 108 pianos with one
coating during a nine-hour working day.
Carriers containing eight complete pianos would handle 144 pianos a
day. A lift sufficiently strong to accomplish any demand placed upon
it can be installed to immerse as many carriers at once as will be
necessary.
A smaller carrier containing four pianos can be installed for the
manufacturer with a small output of pianos, which by the very nature of
its construction is handled more readily than the larger carrier.
In coating both sides of the work a decided protection against
shrinking and warping has been provided. In fact many manufacturers
are taking this precaution by brushing both sides of the work. By the
Standard method the work is automatically coated on both sides at the
same time.
Very little more varnish (not more than 5%) is required by the Standard
system than by the hand method. The inventors' own experiments, as
well as the daily use of the system by manufacturers, shows that more
varnish is wasted about the varnishing room than is required by the
immersion system to coat the unfinished side of the work. With this
method, all of the small amount of varnish that drips off falls back
into the tank.
[Illustration: Fig. 24.--LOWERING PIANO CASES INTO THE VARNISH TANK.]
[Illustration: Fig. 25.--PIANO CASES NEARLY IMMERSED.]
[Illustration: Fig. 26.--PIANO CASES WHOLLY IMMERSED.]
One of the most difficult tasks of the finishing room foreman is to
be certain that the proper reduction is made for the first and other
undercoats. This is entirely eliminated with the use of the Standard
system of piano finishing. This process alone makes it possible to
apply a minimum quantity of varnish sufficient to withstand the strain
of rubbing and polishing. This lessens the possibility of shrinking and
cracking which excessive varnish coats applied by brush involves. The
slower the speed of the lift, the less varnish is applied to the work,
consequently there is a gradual regulation of the amount of varnish for
the separate coats.
[Illustration: Fig. 27.--PIANO CASES ABOUT TO BE DIPPED.]
The foregoing description, together with the accompanying
illustrations, will enable the reader to understand the general method
adopted. It should be added that it is applicable to many other
articles besides piano cases.
The system described was invented and is controlled by the Standard
Varnish Company of London and New York.
WHEELS.
An extremely ingenious but effective machine for coating hickory wheels
with paint or japan is in use at the works of the Ford Motor Company,
Trafford Park, Manchester. It consists of a stationary cylindrical
vessel of exactly the right size to receive a wheel, which, being
placed in position, is at once lowered into a tank containing the
japan. Here it is made to revolve very rapidly, by which means the
japan is thoroughly distributed over every part. Hickory, being a hard
and comparatively non-absorbent wood, the japan might give too thick
a coating if dipped and left to dry in the ordinary way. To prevent
this, the wheel, while still revolving very rapidly, is mechanically
lifted out of the japan, and is held just above it, where it continues
to spin. This has the effect of throwing off the superfluous japan by
centrifugal force. The cylindrical sides of the apparatus catch the
japan, and it runs down into the tank below. The wheels are then taken
out by a man, who wears gloves, are stacked on edge in rows to dry,
and, after an hour or so, they receive a second coat. After twenty-four
hours, or less, they are ready for use.
The advantage of rapidly revolving the wheels is that anything in the
nature of a drip is entirely eliminated. This machine can deal with 300
wheels an hour, so rapid is the process. At the present time the Ford
Works are using 2,000 wheels a week.
SOME TYPICAL PLANTS.
In gathering information of up-to-date character to include in this
book the author has visited various parts of the country, and through
the courtesy of the firms mentioned below has examined the plants used
successfully for the treatment of many different goods. The following
is a brief description of some of the plants inspected, although it by
no means exhausts the list:--
CARRIAGE DEPARTMENT, WOOLWICH ARSENAL.
[Illustration: Fig. 28.--DIPPING A COACH BODY AT WOOLWICH ARSENAL.]
[Illustration: Fig. 29.--GENERAL VIEW OF PAINT DIPPING ROOM AT WOOLWICH
ARSENAL.]
The plant for painting wagons, etc., has been in use for about 12 years
and has been eminently successful, it being found by experience that
a paint applied by dipping proves equally durable to that formerly
applied by means of brushes. Indeed, the durability is increased for
the reason, which has been pointed out elsewhere, that the paint finds
it way into open joints and crevices which could not be reached by
a brush. In some cases a wagon is dipped bodily, while in others it is
dismantled and the different parts are dipped separately; again, the
smaller portions are placed in an open wire basket which is plunged
into the paint. The building in which this painting is done is of
considerable extent and a large paint tank is located at each end. A
wagon on being completed, or in the case of an old wagon, after having
been prepared, is brought to the first tank and is raised from the
ground and lowered into the paint, where it remains for about half a
minute. It is then immediately raised, allowed to drain over a tank for
a few minutes, and then over an inclined floor for a further period.
At the end of about half an hour a workman inspects the wagon or
other article and removes any tears or runs which may have occurred.
The paint being specially prepared this is not usually an arduous
undertaking.
The illustrations show very clearly a coach body in process of dipping.
Overhead rails run throughout the length of the building and upon these
are suspended the painted wagons, which are gradually moved along
with a very little exertion, such rails being slightly inclined to
facilitate this. By the time the series of wagons reach the further end
of the building they are ready to receive a second coat of paint, by
being dipped in the second tank. This being done they are then moved
back, being at once suspended on the rails until quite dry, when they
are hoisted to the upper part of the building, where they are left
suspended until they are required for use. The paint is, of course,
a special one which is supplied in paste form having the necessary
binding ingredients. The colour used is khaki, which is very durable,
being composed of earth colours. The thinning is done on the premises
and white spirit is employed for the purpose, not turpentine, which
would be far too expensive. Formerly benzine was employed, but this
necessitated the use of a fan to take away the fumes which came from
the spirit. Such a fan is not now found to be necessary.
The tanks are fitted with iron covers bearing upon thick felt and are
operated by means of levers placed at a distance, so that should a fire
occur they can be closed at a moment's notice. The hoist is worked
from the ground by electricity. Formerly the operator of the hoist was
located in a cab near the roof, but it was felt that this would be a
dangerous position in case of fire, and he now, as stated, does the
work from the ground. The work done at Woolwich gives an excellent
example of the actual saving which may be effected by using the paint
dipping process. Before the painting plant was put in no fewer than 200
painters were constantly employed; now about 40 are fully able to turn
out the same or even a larger number of wagons in a given time.
JAMES GIBBONS.
Most of the metal sheets as well as finished metal work of various
kinds made at these extensive works at Wolverhampton are finished by
dipping into special enamels or japans made by Messrs. Mander Bros. The
dipping is done by hand and the pieces are placed at the side of the
tank to drain. In some cases it is found necessary to go over the work
slightly with a brush to remove tears, but such work takes only a few
minutes and is used mostly as a precautionary measure.
One coat is usually found sufficient, and at the proper time the iron
sheet or metal article is stoved at 250° F. to 300° F. for two hours.
Many other articles are also dipped successfully.
HARRISON, MCGREGOR & CO.
In the extensive factories of this firm at Leigh, Lancashire, dipping
by immersion has been successfully carried on for some years past.
Various agricultural implements are dipped bodily in a tank of paint
which is fitted with a worm agitator, and is of simple construction.
The iron parts are dipped separately, being supported on suitable
hangers, while the very small parts are placed in wire baskets for
immersion.
PHILLIPS AND SON.
The paint dipping plant at these works, which are situated at
Sherbourne Street, Birmingham, has been in successful operation for
some years past and is applied principally to bedsteads.
The tank holding black japan measures about 5 feet by 18 inches and is
some 9 feet deep. The bedstead head and foot are separately dipped by
hand into the tank which contains black japan, and are immediately hung
on a hook attached to a slowly travelling chain. This chain runs around
a rectangular space, and beneath is a metal lined dripping floor. The
stove is located diagonally from the tank, so that by the time the
bedstead parts reach it the dripping has ceased and they are ready to
be baked. The stoving is done at 320° F., and is continued all night.
One coat is found to be ample.
A very ingenious arrangement is in use for the application of coloured
enamels. Three shallow tanks are mounted on rollers running in angle
irons one above the other in such a manner that any one tank may be
pulled out when required for use free from the others.
As a rule three coats are given for white work and two for green, blue
and most other colours. No white lead is used, but only non-poisonous
colours. The stoving is done mostly overnight at a temperature of 250°
F. A little rubbing down between coats is done with very fine glass or
emery paper. The japans are made by Messrs. Thornley & Knight.
In these works safes are painted, but the work is all done by hand.
THE FORD MOTOR COMPANY.
The extensive works of this company, at Trafford Park, Manchester,
contain as complete a plant for painting, japanning, enamelling and
varnishing, as it has been the pleasure of the author to inspect.
With characteristic thoroughness every detail which will ensure a
first class finish with a minimum of time and labour has been thought
out and applied. The result is that not only is every part dealt with
most expeditiously but one coat of paint is applied to the whole outer
surface of a motor body in the almost incredibly short time of two
minutes. Further details will be found in this book under the heads of
"Flowing-on," "Motor Parts," and "Iron Rods."
MARSHALL, SONS & CO., LTD.
This well-known firm of agricultural implement manufacturers have a
large dipping plant at their Gainsborough works, which they employ
for painting various agricultural machines made principally of red
wood. Some idea of the extent to which this process is applied may be
obtained when it is said that on an average nearly 5,000 pieces pass
through the dipping plant every month. The process is particularly
well adapted for threshing machines and for appliances of the kind
which consist of thousands of holes bored in the wood. If the painting
were done by hand it would take many hours to paint such a machine,
while by dipping it is done even more effectually in a few minutes.
The priming coat only is dipped after knots, etc., have been treated
with shellac. The tank measures 21ft. long by 7ft. deep and 2ft. 3in.
in width. An agitating apparatus is used and the lifting is done by
pneumatic appliances.
HAYWARD BROTHERS AND ECKSTEIN, LIMITED.
The paint dipping plant in use at the works of this firm, at Union
Street, Borough, S.E., is of a comparatively simple type, and consists
of a shallow tank in which various cast iron and steel goods are dipped
in horizontal position. As a rule, one coat of paint is given, but in
certain cases two are required. The bottom of the tank is slanted,
and the contents are stirred up from time to time, but no agitating
apparatus is used. The principal goods painted by dipping are the
frames of Hayward's lights, which are of cast iron and are dipped on
one side only, the other side, after the glass is fitted, being done
by hand. Metal casements are also dipped in considerable numbers, as
well as treads and rises of circular staircases, straight staircases,
balconies, etc. These, being made of ornamental open ironwork, contain
a large number of small shaped holes, and the dipping process is found
to be by far the most effective.
Another speciality of this firm are Hayward's patent steel collapsible
gates. The first coat of paint is applied by dipping; this paint, being
black, dries flat, i.e., without gloss.
THE CRITTALL MANUFACTURING CO., LTD.
These works are at Braintree, Essex, where a large amount of structural
steelwork is produced, the chief manufactures being metal windows
of all kinds, from the well-known steel casement and sash to metal
windows for use in industrial dwellings and specially designed windows
for various climates, steel fireproof doors, skylights, steel office
and works partitions, shop fronts; frictionless ball race runners for
sliding doors, etc.
[Illustration: Fig. 30.--WAGON STORE ROOM, WOOLWICH ARSENAL.]
[Illustration: Fig. 31.--DIPPING CASEMENTS AT THE CRITTALL
MANUFACTURING CO.'S FACTORY, BRAINTREE.]
Perhaps the most noticeable feature of these works as far as our
subject is concerned, is the very complete system of overhead rails,
by means of which the various metal goods produced in the different
finishing shops are conveyed to one or other of the paint tanks and
then, having been left to dry, are taken to store rooms ready for
instant shipment. These rails facilitate handling of the various
goods, and reduce the actual expenditure under this particular item to
a minimum. The rails are L-shaped, the hanger used for each article
or series of articles being of a simple character, consisting of two
wheels bearing on the top of the upright flange, while rods secured by
bolts pass through the horizontal flange and hold it in position.
We will first describe the tank used for dipping metal windows. This is
15ft. long by 12ft. deep and only 1ft. 6in. wide. Attached to the tank
is a large dripping floor measuring some 15ft. by 21ft. covered with
sheet iron and inclined toward the tank, so that the paint which drips
on to it finds its way back into the tank through a grating provided
for the purpose to take off any dried particles. The paint used in
this work is made by Messrs. Docker Brothers, and weighs 13 lbs. to
the gallon; one coat is found sufficient for the purpose. The sashes
or casements being brought in from the finishing room on the overhead
rail, they are lowered into the tank by means of a special lowering
apparatus designed on the premises. Some idea of this may be had from
Fig. 31. In order to keep the load steady during the time it is being
dipped, a slight depression or dip in the rail is made immediately over
the tank. The sashes are only left in the paint for a few seconds, and
are then raised, allowed to drip over the tank for perhaps a minute
or two, and then allowed to drip over the adjacent floor for perhaps
a quarter of an hour or less. They are then taken farther along and
the paint dries in about three hours. Sometimes two, four, six, or
even eight casements may be dipped at the same time. Attached to the
elevating and lowering apparatus are hooks which pass through one
corner of the casements. This causes the parts to hang at an angle
which facilitates running off of the paint.
We come now to the department in which the baking or stoving enamel is
used as applied to metal furniture in general, as mentioned. In this
case the articles are dipped in a manner very similar to that already
described, excepting that a large hook, similar in shape to that shown
in Fig. 32, is used to support the article to be dipped; the wide
opening goes inside the box or file and holds it at an angle so that
when it is lowered into the paint all parts are covered inside and
out. A few minutes are allowed for dripping, and after two or three
hours the articles are ready to be stoved. In this case, Messrs. Docker
Brothers' standard colour, a very pleasing dark green, is used. The
stoving takes three hours at a temperature of 240° F., or higher in
some cases. The tank mentioned is, of course, considerably wider than
that used for casements. The dripping floor is in this case inclined
toward the centre, which in turn is inclined toward the grating just
outside the tank itself. If necessary, special thinners are added
to bring up the gloss, but, as a rule, this is unnecessary. It is
desirable after the article is dipped to go over it once with a small
brush to remove any drips or runs which may possibly appear.
[Illustration: Fig. 32.--HOOK USED FOR SUSPENDING METAL BOXES WHILE
DIPPING.]
Another very important point to be attended to is to exclude all dust,
and for this purpose the Crittall Manufacturing Co. have erected in
this department screens of wire of the finest mesh over windows, so
that no air can pass into the room without the dust being screened off.
EXCLUDING DUST.
A matter of very great importance, yet one which is frequently
overlooked in painting iron and other goods which are to have a glossy
finish, either air dried or stoved, is to exclude dust from the
apartment in which the work is done. In many engineering shops the
nature of the business gives rise to a considerable amount of dust,
and if this is allowed to enter the paint shop it will be fatal to the
appearance of the painted work, as many specks will inevitably settle
on the work and mar its appearance.
[Illustration: Fig. 33--DIPPING CASEMENTS AT BRAINTREE. NOTE THE NARROW
TANK USED FOR THIS CLASS OF WORK.]
A paint shop is best provided with a concrete floor, and this should be
frequently cleaned. The workmen should wear clean overalls, frequently
renewed, and even so small a matter as keeping the hair, beard, etc.,
clean and free from dandruff should be attended to. The doors are
best if double, and thick felt may be used with advantage in the joints
so as to practically seal the opening when the doors are closed. Air
which is admitted, either through ventilators or windows, should be
strained before entering the building, and for this purpose silk gauze
of the finest mesh is usually employed. In some cases, cotton wool in
addition is placed in such a position that the air must pass through
it before entering the room. If these precautions are taken it will be
found that the quality of the work is greatly enhanced.
It may be observed in this connection that it is important also to
provide means of adequate ventilation of the apartment. Moisture
charged air has a bad effect upon paint work. Extreme heat is
unnecessary, but it is very important that the temperature be
maintained at a uniform rate, say 60° F. If the room in which the
painting is done is very hot, the paint will be affected and be likely
to become too thin for its purpose; while, on the other hand, if the
room or articles to be painted are very cold, the paint or enamel will
have a tendency to congeal. Both of these defects can be remedied, as
already stated, by a good system of ventilation and maintaining the
heat, night and day, at a uniform temperature.
A MODEL DRYING ROOM.
The immense importance of providing a uniform temperature and ensuring
an adequate system of ventilation in the room in which goods are placed
for air drying can hardly be exaggerated. Unless such a system is in
use the actual drying may be greatly retarded and the work stand a
chance of being spoiled.
In connection with some of the plant inspected by the author it must
be admitted that the provision made in this respect falls far short of
what is needed. In one case the work of rubbing down was proceeding in
the same shop, although in a different part, in which various goods
which had been dipped were hanging up to dry. It need hardly be said
that under such conditions it was impossible to keep the work free from
specks.
In other cases the drying rooms were inadequate because of the
inefficiency of doors and windows. These, it may be remarked, should
always be double so as to maintain the heat uniformly.
Every varnish user knows that a draught of cold air which is allowed
to reach a coat of varnish while drying is fatal alike to its
appearance and durability. The result is almost certain to be a case
of "blooming," which to the uninitiated may be described as a film not
unlike the bloom of a freshly coloured plum which comes on the surface
of varnish exposed under such conditions. Those unacquainted with
varnish vagaries are apt to regard this trouble as being the result
of inferior materials used in its manufacture. As a matter of fact it
indicates nothing of the kind because, speaking generally, the higher
grades of varnishes are the most susceptible.
Without doubt the best and by far the most economical plan to adopt
is to have a drying room specially built for the purpose of receiving
the articles to be dried. If constructed on scientific principles this
will not only give a uniform temperature entirely free from draughts
and dust but will considerably expedite the work, thereby allowing of
a quicker delivery of goods and effecting a great saving of valuable
floor space.
The author inspected such a drying room at the works of Messrs.
Pinchin, Johnson, and Co., Ltd., at Silvertown, and a description of
it will doubtless prove of interest. It is built of 5-ply wood and is
about 16 feet square, sufficiently large to hold two full-sized motor
bodies or several dozen perambulators, hand wagons, etc. The actual
size may, of course, be varied according to the size of and number of
articles to be dried. Air is admitted through two ducts situated close
to the floor through fine wire gauze, which is provided with a lifting
cover by which the amount of air admitted may be regulated.
Immediately over the two air ducts mentioned is a coil of steam
pipes which heats the air to, say, 110° F. This, of course, causes
it to rise toward the ceiling, but the angle between the ceiling and
wall is rounded off by a cove, so that the current of heated air is
directed along the ceiling toward the centre of the room where there
is another cove and beneath it a coil of cold air pipes which lowers
the temperature somewhat. Thus is created a constant motion of the air
which may be regarded as the essence of the system.
But there is another very important provision in the shape of an
automatic control. This cuts off the steam when any desired heat is
attained so that when the drying room is filled up at night before the
works close it can safely be left until the morning when the drop in
temperature will not be more than 2 degrees. The steam may be admitted
at, say, 10 lbs. pressure, but as soon as the room is heated from 2 to
2½ lbs. will be found to be sufficient. The actual time for heating
the room to 120° F. is from 15 to 20 minutes.
The speed with which work is turned out by this well-considered adjunct
may be gauged from the fact that a panel may receive one coat of enamel
and two coats of flatting varnish in one day, or four coats of japan in
the same period.
In addition to the advantages mentioned is the most important one
that the drying room renders the manufacturer who is fortunate enough
to possess one quite independent of the weather. In the words of the
inventors and patentees, "one enabled by its use to create one's own
climate."
[Illustration: Fig. 34.--DESIGN FOR SHOW CARD DONE BY SPRAYING.]
CHAPTER IV.
PAINTS FOR DIPPING.
It need hardly be said that the paint employed for this purpose must be
of a special character. There are several firms of manufacturers who
make a speciality of this class of paints and supply them either ready
for use or in paste form, requiring only the addition of white spirit
or other suitable thinner to bring them to the right consistency. The
following may be considered as the necessary qualities of a paint
suitable for this purpose:--
1. It must dry hard in not less than six hours.
2. The pigment must be of such a specific gravity that when mixed with
a suitable vehicle or thinner to form a paint the pigment will not
quickly deposit at the bottom of the tank or settle out.
3. The consistency of the paint must be so arranged that only a minimum
quantity will run off, while it must not be so thick as to give rise to
tears or runs.
White lead which has a specific gravity of about 6.750 is for the
reason mentioned usually considered too heavy, and in the case of a
white or grey paint, zinc oxide which has a specific gravity of 5.470
is used in preference. The following colours may also be successfully
employed, because of their low specific gravity, viz., Oxford ochre (s.
g. 2.822), Venetian red (s. g. 3.560), Indian red (4.732), golden ochre
(3.107), Italian raw sienna (3.081), burnt sienna (3.477), Turkey umber
(3.496), Prussian blue (1.956), bone black (2.319).
It will be observed that the earth colours, such as ochre, sienna,
umber, etc., are all light pigments, and as they are also recognised
as being the most durable, they are eminently well suited for use in
many positions, although the colour is not always very agreeable.
Precipitated barytes (s. g. 4.144) can be used up to, say, a proportion
of 10 per cent.--not more; red lead (s. g. 8.681) cannot be used for
this purpose, as it is far too heavy, and the same applies to English
vermilion (s. g. 7.726). If, however, a bright colour is required, it
may be obtained by dipping in Venetian red or Indian red and giving a
second coat of crimson lake (s. g. 1.898), but a coat of varnish should
be sprayed upon this for protective purposes.
In considering this subject, it is well to remember that much will
depend upon the thickness of the vehicle used, as, clearly, a fairly
heavy pigment will settle out in a thin vehicle much quicker than it
would in a comparatively thick one. The successful paint, therefore, is
one in which both considerations are taken into account.
Very rarely indeed does it pay manufacturers to attempt to grind or
prepare paints themselves, and much greater satisfaction will be
obtained by getting supplies from a reputable firm who have made a
special study of the subject.
Sometimes a white paint is required for dipping, and in that case
30 lbs. of sublimed white lead, 10 lbs. of zinc oxide and 6 lbs. of
gilders' whiting, with 4 lbs. of asbestine pulp, mixed with 9 lbs. of
raw linseed oil, will be found to give good results.
A paint which dries with a gloss is often desired for the finish of
many articles, and can be readily obtained by first priming, then
giving a finishing coat of paint on it which has been mixed with
sufficient varnish to produce the desired gloss. In some cases three
coats may be given, namely, the first or priming coat, the second,
which should be flat, or semi-flat, and the third a coat of varnish
paint, which will dry with a gloss. It should be pointed out, however,
that the finish obtained by these means is not a little inferior to
that which may be produced by using over the priming one or more coats
of flat paint of the desired colour and finishing with a coat of
suitable varnish, which may be applied either by dipping or spraying,
according to circumstances. A point here worthy of mention is one which
every house painter is or should be well acquainted with, and that is
that the coats of paint that are superimposed should be alternatively
flat, _i.e._, without gloss, and glossy, in order that each may adhere
closely to the other. If the article to be painted is wood or any other
material which is of an absorbent character, a comparatively large
amount of turpentine and oil must be mixed with it in order to allow
for suction. This will dry with a semi-flat finish, and a glossy coat
or one having more oil in its composition, may be applied over it. If
a further coat is required it should be flat or nearly so, and in that
case a finishing coat of varnish will probably be required. The paints
for these purposes may be purchased ready made or ready for thinning
down, from firms who have made a special study of the requirements.
The question sometimes arises as to whether paint dipping or spraying
can be used advantageously when in the finish two or more colours are
to be used. As a rule the difficulties can be overcome by dipping first
or even the second coat, spraying on the third or finishing coat, using
specially prepared masks or shields over those parts which are not to
be painted with the particular colour in use.
The following useful information is taken from "White Paints and
Painting Materials," by W. G. Scott, who was for sixteen years
connected as paint expert with the Milwaukee Harvester Company and the
J. I. Case Threshing Machinery Co. Mr. Scott therefore speaks from a
wide experience. He says:--
A certain amount of oil must be present in dipping paints to act as
a binder, and it is advisable to add a small quantity of varnish to
hold the paint together. The desired features in a good dipping paint
are: freedom of flow and proper drip; sufficient binder to prevent
chalkiness and produce a firm coat; covering capacity and an even
distribution of the paint.
Non-absorbent surfaces like metal and hard wood require less oil than
the absorbent soft woods.
In the former case there is little or no penetration of the liquid
portion of the paint, but with pine, bass wood, white wood, poplar,
etc., nearly all of the liquid is absorbed or taken up by the
wood, consequently with benzine only as a thinner there will not
be sufficient binder present to hold the pigment when the thinner
evaporates.
Whereas 5 lbs. of paste pigment or colour ground in oil and thinned
with a gallon of benzine would produce a suitable primer on iron or
other non-absorbent material, it would not answer for soft wood.
Dipping paints, as a rule, contain from 4 to 10 lbs. of paste per
gallon of thinner, the primer containing less paste than the second
coat paints.
The composition of the paste colour has much to do with the dipping
paint; for instance, 5 lbs. of paste white lead to the gallon of
thinner will cover and work better than a mixture consisting of half
white lead and the other half made up of transparent pigments like
china clay, barytes, etc., nevertheless a small amount of inert
material is generally understood to be an improvement in the way of
durability.
Asbestine, whiting, silica and china clay are the inert materials most
often used in paste goods for dipping purposes.
Asbestine probably helps to hold the pigments in suspension better
than any of the others and answers nicely for dipping paints, but, as
previously mentioned, does not allow the paint to level out when used
with a brush.
China clay, on account of its low specific gravity, is much favoured as
a suspension agent, but materially lessens the opacity of the paint.
A small amount of whiting is a good addition to a dipping paint, as
it carries down much of the dirt and heavy particles usually produced
during the process of dipping. Silica gives the paint "tooth," and by
some authorities is considered an actual necessity in primers which are
intended to be sand-papered.
White lead and zinc oxide are the two ideal white pigments considered
from a dipping standpoint, and it will be found that the majority of
dipping paste paints on the market contain a notable quantity of zinc
oxide, either straight or in the form of zinc lead.
Zinc oxide is generally the predominating pigment in the white and
tinted paste paints, and is usually associated with white lead (basic
carbonate), zinc lead, and sublimed white lead, mixed with more or less
inert material according to the ideas of the manufacturer or in order
to cheapen the product.
The admixture of inert material with the coloured pigments requires
some knowledge of the composition of the coloured pigment; for
instance, lampblack might be safely mixed with asbestine, whiting,
silica, barytes, etc., without detriment, but yellow ochre containing,
naturally, considerable clay and silica would hardly permit of any
great addition of china clay or silica.
The strong iron oxides, chrome greens and similar tinting colours will
stand a large quantity of inert material when the paint is to be used
as a body colour, but for varnish colours it is customary to use the
chemically pure colours and less paste per gallon of thinner.
Paste paint for varnish colours is frequently ground in oil, in japan,
or in a mixture of the two, but far better results are obtained by
grinding the dry pigment in varnish thinned to a grinding consistency
with a little turpentine. A varnish with a viscosity of 20 (water = 1)
which gives a stiff mix with, say, 5 lbs. of pigment will, when thinned
to a viscosity of that of raw oil, _i.e._, a viscosity of 4, take about
20 lbs. of pigment.
No set rule can be given for the kind and amount of thinners to
be used in dipping paints for various purposes, but the following
proportions[1] will furnish a key to the general mixtures used:--
[Footnote 1: The figures given relate to an American gallon, which
contains 231 cubic inches, while an English imperial gallon contains
277¼ cubic inches. For practical purposes the latter may be
considered one-fifth greater than the former.]
PRIMERS FOR METAL.
4 to 5 lbs. of paste thinned with 7/8 to 31/32 gallon of benzine or
turpentine and 1/8 to 1/32 gallon of mixing varnish.
PRIMERS FOR HARD WOOD.
4 to 5 lbs. of paste thinned with 15/16 gallon benzine or turpentine,
3/64 gallon raw oil, 1/64 gallon mixing varnish.
PRIMERS FOR SOFT WOOD.
4 to 7 lbs. paste thinned with ½ to ¾ gallon benzine or turpentine,
15/32 to 15/64 gallon raw oil, 1/32 to 1/64 gallon varnish.
In some cases, with very soft, porous woods, it may be necessary to add
more raw oil and some japan or liquid drier, but too much drier must
not be added, as it will shorten the "flow."
SECOND COAT DIPPING PAINTS.
5 to 10 lbs. of paste thinned entirely with benzine or turpentine, or
with 7/8 gallon of solvent and variable proportions of oil and varnish
according to the surface desired.
Varnish is advocated in all of these mixtures, as it helps to hold the
solids and liquids together and prevent separation; it also induces
toughness.
It is essential that a varnish be used which will mix perfectly with
oil and benzine at a temperature of 60° F.
Varnish colours are best thinned with turpentine, but owing to the high
price of turpentine the large factories insist on using benzine or some
of the turpentine substitutes now on the market.
The fact that some of the turpentine substitutes work better and give a
better "flow" with the paint and varnish, is due to the fact that most
of them contain a heavy distillate of petroleum similar to kerosene.
Kerosene oil has the double property of thinning and imparting "flow"
to either paint or varnish, but retards the drying, hence too much must
not be used.
Damar varnish, which will not stand thinning with benzine without
separation of the gum or becoming cloudy, will permit of dilution with
kerosene to quite an extent.
So far as durability is concerned, kerosene imparts more durability and
is more waterproof than any of the other thinners. Combined with rosin
and manganese oxide, it may be made to dry like raw linseed oil, but,
of course, does not possess the same properties.
In dipping paints, as in all other kinds of paints, good judgment must
be used in the mixing, and it is absolutely essential that paints for
soft wood, or other absorbent material, contain enough oil, or binder,
to hold the pigment.
WHITE PASTE PRIMER. EXTRA FINE.
300 lbs. white lead (carbonate).
150 " zinc oxide.
50 " floated silica.
Grind in
10 gal. raw linseed oil.
Product = 575 lbs.
This paste is thinned with turpentine or benzine for dipping purposes
in the following manner:--
WHITE DIP FOR METAL.
100 lbs. of white paste.
14 gal. turpentine or benzine.
½ " pale mixing varnish.
¼ " white liquid drier.
WHITE DIP FOR HARD WOOD.
100 lbs. white paste.
13 gal. turpentine or benzine.
2 " raw linseed oil.
¼ " pale mixing varnish.
½ " white liquid drier.
WHITE DIP FOR SOFT WOOD.
100 lbs. white paste.
12 gal. turpentine or benzine.
6 " raw linseed oil.
¾ " white liquid drier.
The pale mixing varnish and the white liquid drier must not liver with
lead or zinc, otherwise, the paint in the tank will thicken continually.
The above formula produces one of the best paints known, and it is
certainly not a cheap paint.
WHITE SPIRIT.
As already mentioned, many firms who use the paint dipping process
buy their paint in paste form with the requisite amount of driers
added, and thin it themselves with white spirit, which is a petroleum
product specially prepared for the purpose. Turpentine is, of course,
too expensive, and the spirit costs, under normal conditions, little
more than one-third of the price, although exact figures cannot be
given owing to the fluctuation in the price of these materials. Some
manufacturers use a white spirit, to which has been added from 25 to 30
per cent. of genuine American turpentine. This, of course, renders the
mixture somewhat expensive, and possesses no advantage excepting that
it gives the characteristic smell of turpentine; but this, it appears,
is not important in a factory, and the pure white spirit is quite
suitable in itself.
According to Mr. S. Roy Illingworth, A.R.C.Sc., A.I.C., B.Sc., Lond.,
expert to the Gas Lighting and Improvement Co., Ltd., turpentine
substitutes were first placed on the market about 30 years ago, and
consisted at that time of a mixture of turpentine and kerosene oil.
Investigations led to the production of white spirit, drying as quickly
as turpentine, or even quicker if desired. Several grades of this
material are made, varying in flash-point from 80° up to 150°. The
flash-point of genuine turpentine, it may be mentioned in passing, is
90° to 91°, and the 90° flash-point spirit is the one usually employed
for painting purposes, although the 80° flash-point would answer
equally well for dipping. The best grade is practically free from smell
and is suitable for admixture in all paints, excepting those having a
bitumastic or asphaltic base, or paints in which very common driers
containing cheap rosin are used. A rough-and-ready test as to the
quality of white spirit is to dip a piece of blotting-paper into it
and hang it up to dry. In the course of an hour-and-a-half it should
have wholly disappeared, leaving no smell or stain behind it. If there
should be a stain the sample should be viewed with suspicion. Another
test of the same kind is to drop a little spirit on a piece of white
writing paper and to leave it for three-quarters of an hour, when it
should have disappeared without leaving a stain. In addition to these
tests it might be advisable to mix a little spirit with paint and to
try it experimentally.
In the evaporation of turpentine it is usually admitted that a small
proportion, say, from ·25 to ·50, is left behind owing to oxidation.
In the case of best white spirit, however, very little residue will
be left behind, certainly not sufficient quantity to interfere in any
way with the drying. The use of the spirit has proved so successful
that practically nothing else is now employed in paint dipping. It is,
however, important, of course, that the best quality white spirit be
used, but as this is so much less in cost than turpentine, there is no
temptation to use an inferior quality.
THE QUANTITY OF PAINT REQUIRED FOR DIPPING AND SPRAYING.
Speaking generally, rather less paint will be required when it is
applied by dipping, or spraying, than is necessary when it is applied
with a brush. But there are many exceptions, particularly in spraying,
where it may be necessary to give a coat considerably thicker than
usual.
The following table will be found useful as a guide, but it should be
remembered that the actual space covered will vary considerably with
different grades of paint, so that the table should only be taken as
approximately correct. In cases of doubt, careful calculations should
be made after a given quantity of paint, varnish, or lacquer has been
applied to a surface of known area. This will serve as a useful guide
in ordering in the future. It need hardly be said that the quantity of
paint necessary will vary largely with the surface to which the paint
is applied. For example, an absorbent surface, such as unprimed wood,
will require much more paint than metal work, which absorbs little or
none.
SPREADING CAPACITY OF PAINTS.
Per Gallon Per Gallon
on Wood. on Metal.
Priming Coats 60 to 70 90 to 100
Mixed Paint 2nd coat 85 to 90 100 to 120
Varnish (on paint) 95 to 110 120 to 130
Lacquer (on paint) 100 to 115 130 to 150
Enamel (on paint) 75 to 80 85 to 95
CHAPTER V.
PAINTING BY COMPRESSED AIR.
THE EVOLUTION OF THE APPARATUS EMPLOYED.
By way of introduction to the subject of the application of paints,
enamels, lacquers, varnishes, stains, etc., by means of compressed air,
a few notes on the development of the method may be given, if only with
the object of correcting the impression, which sometimes exists, that
such apparatus as is now employed is more or less of an experimental
character.
The early attempts to apply paint, etc., to articles other than by the
old method of brushing were mainly carried out with a type of machine
still largely used for whitewashing, and the principle adopted was
to partly fill a convenient tank with the paint or whitewash and to
pump a pressure of 35 to 40 lbs. into the tank by means of a suitable
hand pump. The paint was forced through a flexible tube attached to a
connection near the bottom of the tank, and at the other end of the
tube was a simple form of nozzle with a trigger control for the paint.
It may be said at once that this method was doomed to failure owing to
the underlying principle being at fault. While eminently suitable for
applying whitewash or distemper, it was hopeless for paint of a more
viscous character, owing to the fact that the latter was not atomised
as it issued from the nozzle.
The type of machines referred to, viz., those which are used for
spraying lime white, distemper, whitewash, etc., are fully described
and illustrated in another chapter.
After failing to achieve satisfactory results with such simple
apparatus when applying viscous paints, etc., further experiments
were carried out with a somewhat different type, commonly known as
the "kettle" type of sprayer. The principle employed was to employ
compressed air, supplied, in this case, not from a hand pump but some
form of power compressor, and at a pressure varying from 20 to 50 lbs.
per square inch.
The air was delivered through a nozzle controlled by a convenient
plunger or trigger type of valve, and impinged at an angle across a
similar nozzle communicating with the paint receptacle of the sprayer.
The action of the air impinging on or across the paint nozzle created
a vacuum in the paint tube, and thereby sucked up the paint from the
receptacle and gave a fan-shaped spray. Up to a point these experiments
proved satisfactory, but still did not overcome the difficulty of
successfully dealing with intricate shapes, small articles, and
particularly in applying heavy paints with fair percentages of varnish
embodied therein.
THE CONCENTRIC FORM OF SPRAY.
Attention was therefore directed to the concentric jet form of sprayer,
and this is now almost universally employed where painting, enamelling,
etc., is carried out on a large scale.
The advantages of the latter type are many, and in addition to being
designed, in most cases, to produce the greatest effect with the least
possible consumption of air, they are also capable of applying the
paint in very finely divided particles to the smallest work, such as
buttons, imitation jewellery, small electrical camera parts, or of
applying silky coats to such large work as motor bodies, constructional
iron work, large tinplate work, agricultural machinery, domestic gas
apparatus, etc. at a speed approximating to four to ten times the speed
of handwork, and giving a far superior finish, in many cases with less
coats.
Many people who contemplate the subject of painting with a spray
think only of a smother of paint being discharged from a nozzle. They
are not aware that the colour can be better controlled in a suitably
constructed spray than is possible with a hog's hair brush.
The flow of paint is stopped or started instantly, and the amount
of paint delivered is at all times under perfect control, so that a
quantity corresponding to that delivered by a ¼-inch brush or pencil
can be increased to the quantity distributed by a 4-inch brush in a
single stroke. In other words, you have a tool which is the equivalent
of half a dozen brushes ranging from ¼ inch to 4 inch in width.
A little practice is, of course, necessary to master the instrument,
but nothing like the practice which is required for successful painting
with hog's hair.
The principal care is to put on the paint until the beads of paint
coalesce. Too much would make the paint run, too little would not leave
the surface covered. When properly done the surface is superior to
other painting, as the hairs of the brush are not dragged through it to
disturb the evenness of the surface.
The air pressure required for painting varies with the consistency of
the paint, its viscosity as well as its thickness. Some liquids have
a quality of stringiness or hanging together which require a higher
pressure to break up.
Thin lacquers and varnishes may be sprayed with 18 or 20 lbs. to the
square inch, and from that to about 50 lbs. will cover most classes of
paint.
The lowest pressure at which a paint breaks up is the best pressure to
use, as high pressures have a tendency to make more dust and put fine
particles of paint in the air, where they are not wanted.
The volume of air has also to be considered. This varies with the size
of the aperture through which it exhausts and to some extent with the
pressure--for a small nozzle such as is used for lacquers and thin
liquids, say, one cubic foot of free air per minute, and up to 3 cubic
feet for oil paints.
When it is stated that a pistol sprayer consumes say two cubic ft. of
free air per minute, it means when working almost continuously, but as
the periods of actual work do not represent more than two-thirds of the
actual number of working hours, there is a margin left. Nevertheless,
it would be unsafe to state a lower figure, for in some cases where
convenient feeding of the work to the operator is arranged, the
consumption of air is continuous.
It should also be remembered that the air is used for other purposes,
i.e., a small amount is used to provide a pressure feed of colour to
the instrument in many cases, and where a heater is employed, a small
amount of air is bypassed through the pistol to keep this warm when
spraying is momentarily stopped. Although the practice of heating the
air slightly increases the ultimate efficiency of a given compressor,
yet it is unwise to count too much upon this fact.
In submitting the following figures as to air consumption, the
Airostyle pistol has been taken as a type:--
For work with a tip and needle of 1 m/m. dia., 1 cub. ft. per minute;
1½ m/m. dia., 1¾ cub. ft.; 2 m/m. dia., 2½ cub. ft.; 2½ m/m. dia., 3
cub. ft.; 2½-3 m/m. dia., 3½-4 cub. ft.; 4½ m/m. dia., 5 cub. ft.
These consumptions naturally vary slightly with the adjustment of the
nozzle of the pistol, but they are from actual tests and so may be
taken as authoritative.
CHAPTER VI.
TYPES OF SPRAYING APPARATUS.
We now come to a consideration of the different appliances by means
of which the actual spraying is effected, and in order to avoid any
suspicion of partiality the review of instruments, etc., in use will be
dealt with alphabetically.
THE AEROGRAPH.
[Illustration: Fig. 35--THE AEROGRAPH SPRAYING INSTRUMENT.]
First, therefore, comes the Aerograph Co.'s Spray Painter. This
instrument is of the concentric jet type, and was one of the first of
the kind made in Europe. It is capable of excellent work. In Fig. 35
is shown one form of the handpiece. A flexible tube for compressed
air connects with the nipple A. The finger lever F controls both the
air valve and a colour valve in the nozzle N, so that little or much
colour may be allowed to pass out into the current of escaping air.
The colour may be supplied under pressure, through a flexible tube from
a large paint pot, and pass through the tube P to the nozzle N, or in
smaller quantities from a cup C, which is attachable at B, and when so
attached cuts off the supply through the tube P. This cup is useful
when small quantities of colour are wanted with frequent changes. A
ball joint permits work to be done in either an upward or downward
direction.
[Illustration: Fig. 36.--FORM OF AEROGRAPH SUITABLE FOR SPRAYING
VERTICALLY OR AT AN ANGLE.]
[Illustration: Fig. 37.--THE AEROGRAPH ELECTRIC MOTOR OUTFIT.]
[Illustration: Fig. 38.--PAINTING A GASOMETER.]
In Fig. 36 is illustrated a pistol pattern of the Aerograph, which has
a large side cup which can be sprayed at any angle, being adjusted to
facilitate spraying in an upward, downward or horizontal position. Thus
work can be done by it on table, wall or ceiling. The cup referred to
contains the paint or other liquid to be sprayed, and a series of cups
may be provided for a quick change of colour, if desired, as will be
readily understood.
In cases where electric power is available, the electric motor outfit
shown in Fig. 37 will be found very serviceable. It may be described
as a "spray painter" outfit complete, and it includes a 1 h.p. motor
mounted on a trolley ready for use, which can be employed for many
different classes of work. In Fig. 38 it is shown being used for
spraying paint on a gas holder. It would appear that this outfit might
be employed for ship bottom painting, provided that the necessary
scaffolding or its equivalent were available.
[Illustration: Fig. 39.--SMALL AEROGRAPH FOR DELICATE WORK, LINING,
LETTERING, ETC.]
Going to the other extreme, a form of Aerograph, suitable for very
delicate work, is shown in Fig. 39. This may be used for photograph
retouching, pottery, and small decorative work generally--in fact, it
is suitable for any work requiring delicacy of work.
In another chapter the subject of artistic work done by means of
compressed air is considered at some length, and a number of specimens
of work executed by this process are given.
THE AERON.
The system of spraying is manufactured by the De Vilbiss Manufacturing
Co., Toledo, Ohio, U.S.A., and 71, Newman Street, London, W.
The method consists, briefly, in spraying stain, shellac, varnish, or
enamel, as the case may be, on the work by the means of compressed air,
under a pressure varying from 30 to 80 pounds per square inch.
The necessary outfit comprises the Aeron sprayer itself--which is made
in two styles and several sizes--the air compressor and receiver, an
air transformer set, for regulating the pressure and purifying the air
supply, a steel Fumexer, in which the work is done, and an exhaust fan
to disperse the vapours or fumes resulting from the atomising of the
finishing material. Besides these necessary appliances, turn-tables are
used where advisable to facilitate the handling of the work while the
"aeroning" is being done.
The two styles of Aerons are shown in the illustrations, each connected
with an air transformer set to which the air supply pipe is attached.
In one style of Aeron the finishing material is carried in a pint
or quart capacity cup forming a part of the Aeron itself. The other
machine takes its supply from a five-gallon container suspended above
the nozzle. The work is placed in the Fumexer on the turn-table, which
can be tilted at any convenient angle and revolved by hand, and is
coated on the top, sides, and front, with the drawers in place. Drawers
may also be finished inside by this process.
A full coat can be applied to a vertical surface as well as to one in
a horizontal position. There are two reasons why. It is impossible to
put on a perfectly uniform coat with a brush, especially on a vertical
surface, and runs and sags are caused by the heavier portions of the
coat dropping down over the lighter coated spots. With the Aeron a
uniform coat of varnish is applied, and it is a fact that as the coat
is the same over the entire surface it will not run, even if it is
as heavy as a brush coat, which would show sags. The second reason
is that an Aeron coat sets somewhat quicker than a brush coat, owing
to a slight evaporation of the solvent caused by the action of the
compressed air. Again, since the coat is uniform it sets uniformly. For
the same reason the final drying is hastened to some degree.
In brushing flat horizontal surfaces where a heavy coat is applied it
is almost impossible to avoid fatty edges, and in brushing carved or
ornamental relief work the low spots are sure to collect more varnish
than the high places. Corners and edges in panel work are also causes
of difficulty in this respect. In using the Aeron the surface varnished
is covered uniformly and evenly, whether flat, panelled or carved, with
one sweep of the machine at an even speed. Consequently, heavy spots,
runs and fatty edges are entirely avoided.
In applying finishes with the Aeron a slight reduction of the material
with turpentine or other solvents is logical; with some materials,
necessary. Reducing is logical on account of the slight evaporation
of solvent previously mentioned. In other words, in order to have the
Aeron application of the same consistency after reaching the surface
as it is when brushed, a reduction of from 5 to 10 per cent. would be
required. This is not always desirable by any means, especially in the
case of the heavy gloss coat spoken of. Whenever a free-flowing coach
varnish is used, reducing is not necessary. Conditions in different
plants govern this matter to a great extent.
Rubbing varnishes are usually reduced slightly, as a full-bodied, heavy
coat is not required, also because a rubbing varnish does not flow as
readily as a coach varnish. On account of this evenness of the coat,
an Aeron coat of rubbing varnish is somewhat more easily and quickly
rubbed either by hand or by machine.
Undercoat varnishes are reduced to some extent for Aeron work for
similar reasons. They are also more easily sanded than when brushed.
Pigments, primers or first coaters are Aeroned to better advantage if
the pigment content is less than for brushing. It is also sometimes
desirable and expedient to use a more finely ground pigment.
Flat finishes are applied to great advantage, and, because of greater
uniformity of surface, more closely resemble a rubbed finish than when
brushed.
This spray offers perhaps greater advantages in the application of
shellacs than with other materials. It is a matter of common knowledge
that shellac is very difficult to brush, while, on the other hand, it
sprays easily. Instead of cutting the gum 4 or 5 pounds to the gallon
of alcohol, as for brushing, the material is used in the proportion
of 2½ to 3 pounds of gum to the gallon. The sprayed coat of shellac
is perfectly smooth and uniform, and requires practically no sanding
compared with the work necessary to sand a brushed coat.
The Aeron is simple and easy to operate, and a week's work is
sufficient to make an efficient and expert operator of the average man.
The work is clean, and, what is more, is healthful and sanitary, as all
vapours and fumes are removed from the finishing room by the exhaust
fan used with each outfit.
Cleaning the Aeron is accomplished by spraying a solvent through the
nozzle instead of the finishing material, and the whole machine may be
placed in a can of thinner overnight if desired. It is necessary to
clean the Aeron but once a day if it is used more or less continuously.
The whole operation of cleaning may be performed in a minute or two.
There is usually some loss in finishing material when the Aeron is
used, though this is hardly noticeable except on small work, when it
may amount to 15 or 20 per cent. In many cases there is no waste, in
others an actual saving--where coats are eliminated by the use of the
machine. On an average, however, there is some slight loss--largely
of the solvent used in reducing the material. In any event, however,
the waste is offset many times by the saving effected in time and
labour, without taking into consideration the saving in floor space,
the greater ease in handling the work, the better quality of the work
done, the advantage to the workmen, and, finally, the general all-round
convenience of the Aeron system.
DESCRIPTION OF THE ILLUSTRATIONS.
We will now give a description of the illustrations of the different
parts of the Aeron. Fig. 40 shows the attached cup straight barrel
Aeron, which can be fitted with either metal or glass cups. Metal cup
is the standard equipment.
Attached cup Aerons can be furnished with four sizes of nozzles:
F--.047" dia., E--.070" dia., D--.081" dia., and C--.094" dia. These
nozzles are selected according to the nature of the work that is to be
done.
Fig. 41 shows an attached cup angle barrel Aeron, a type of advantage
in spraying work lying in a horizontal position.
In some classes of work, where the liquid to be sprayed is apt to
settle, an agitator is required, such as is shown in Fig. 42.
In Fig. 43 is shown an attached cup Aeron with type V double nozzle
spray head. This type is especially adapted for the finishing of large
surfaces, such as automobile bodies, case furniture, etc.
The V spray head shown separately in the above illustration is
interchangeable with the single nozzle spray head, and can be attached
to any standard Aeron.
Type G Aeron is illustrated in Fig. 44. The nozzle is ·027 inch in
diameter This Aeron can also be furnished with other sizes of nozzles
to special order.
[Illustration: Fig. 40.]
[Illustration: Fig. 41.]
[Illustration: Fig. 42.]
[Illustration: Fig. 43.]
[Illustration: Fig. 44.]
[Illustration: Fig. 45.]
[Illustration: Fig. 46.]
[Illustration: Fig. 47.]
In Fig. 45 are shown various attachments used with this form of
sprayer. At the top left-hand corner is a cup holder and screws, and on
the right, metal or glass cups. Beneath are cleaning pail and length of
pressure tubing with connections.
Fig. 46 shows the construction of the Aeron, the parts being
disassembled for ease of cleaning.
We now come to the type of Aerons which take their supply of material
from a five-gallon tank placed above the level of the nozzle, the fluid
flowing down by gravity. This arrangement offers all the advantages of
the pressure feed tank type with none of its disadvantages. It is shown
in Figs. 47 and 48.
The next type is termed the M Aeron with V-A spray head and is
illustrated in Fig. 47.
There is the same advantage in the use of this Aeron as with the
former type in that the supply of material is taken from a container
placed overhead, the fluid flowing down by gravity. The slightest pull
upon the trigger releases the material instantly--the varying of the
pressure adjusts the flow automatically. As with the type L there is
but one adjustment.
This type Aeron is built for large work. It produces a "wide spray,"
similar to the V spray head, which covers large surfaces with
remarkable rapidity.
The nozzle can be turned so that a full, fan-like spray is projected
horizontally, vertically, or in any intermediate position.
A container with agitator and hose for types L and M Aerons is shown in
Fig. 50.
It is drawn from one sheet of steel and is heavily tinned to prevent
rust.
The standard and block and tackle (Fig. 49) are furnished for holding
the container above the level of the Aeron. The block and tackle,
which is of the safety, self-locking type, is recommended where it is
possible to obtain a ceiling fastening. The standard (Fig. 51) can be
used if the block and tackle is impracticable.
The air transformer set (Fig. 52) is for the purpose of regulating
and purifying the compressed air, and is a necessity with each Aeron
installed. The air duster (D) is a valuable addition to the equipment
for removing loose dust or dirt from the work before finishing.
The auto-filter (S) is for removing dust, grit, and oil from the
compressed air. The auto-regulator and gauge (R) makes possible
the regulating of the air pressure between 5 and 80 pounds, simply
by turning a thumb-screw. The auto-condenser (C) is for separating
moisture from the compressed air.
Full details of the air compressor and other special appliances used in
connection with the Aeron will be found elsewhere.
[Illustration: Fig. 48.]
[Illustration: Fig. 49.]
[Illustration: Fig. 50.]
[Illustration: Fig. 51.]
[Illustration: Fig. 52.]
THE AIROSTYLE.
Next comes the Airostyle and Lithos, Ltd., with their "Airostyle" type
Record, also a concentric jet-type, an illustration of which is given
in Fig. 55 and a section of which we give also in Fig. 54. This type
is largely used for small, medium or large work, and is considered to
be extremely sensitive and very fast in operation. It has a gunmetal
casting for the main body, and all wearing parts are of steel, tempered
or case hardened.
It is supplied either with or without pressure fed accessories,
although the makers are strong advocates of pressure feeds for most
work, and with which they have met considerable success.
In addition to the Record Pistol this firm makes other types, and
in order must be mentioned the type "Ultra" for use where frequent
changes of colour may be necessary, and where no continuous colour feed
is required. This type is specially adapted for stencilling in oil
colours, and is illustrated in Fig. 56.
Another type about to be introduced is shown in Fig. 53, for small and
medium work, simplicity of construction and ease of adjustment being
specially claimed for this type. This type is called the Airostyle
Pistol "M."
Yet other type of Airostyle may be mentioned for smaller work, namely,
the "Stencil and Universal Lustre and Photo," which is illustrated in
Fig. 53.
These types are mainly employed for decorative work, and give a very
wide selection, but save that they are employed in process work and for
textile goods, they do not enter into the scope of this book.
[Illustration: Fig. 53.--AIROSTYLE TYPE PHOTO.]
As the pistol type is used for all general painting and japanning, the
adjustment of this may be advantageously explained in greater detail,
and referring to Fig. 54 the instructions are as follows:--
[Illustration: Fig. 54.--SECTION SHOWING CONSTRUCTION OF THE AIROSTYLE.]
[Illustration: Fig. 55.--AIROSTYLE TYPE "RECORD" WITH UNION FOR
CONTINUOUS SUPPLY. A.--SMALL PRESSURE BOWL. B.--SMALL SIMPLE BOWL.]
If a wide spray is required the nozzle 8 is unscrewed to a small
extent and then locked by means of a small ring 8a, but if a narrow
spray is wished for, the nozzle 8 is screwed on farther and locked in
position. On all-round work one position serves, that is, a position
in which the recessed point of the nozzle coincides with the end of
the tip 9, which just allows the needle 5 to project through it. If it
should happen that a leakage of colour occurs through 9 when spraying
is suspended, this may be obviated by giving an increased tension
to spring 15 which may be obtained by screwing in the spring box 16
slightly. It may happen that some foreign matter becomes lodged in
9, in which case the pistol from the colour tube must be first
disconnected, the nose 4 removed and the parts brushed or swilled
with turps or spirit. This having been effected, the nose 4 will be
replaced, care being taken that the washer 3 beds down on its seating
in the body of the pistol.
[Illustration: Fig. 56.--AIROSTYLE TYPE "ULTRA."]
It is well to provide for any possible contingencies which may arise,
and it may, therefore, be remarked that if any leakage of air occurs
through the air valve 19, it will probably be caused by some grit to be
found on the face of air valve washer 20, and to remove this the handle
can be taken off by unscrewing the milled nut 25 and the valve body
23 in order to get to the air valve. The replacement of the parts is
simple.
The adjustment of the pistol for working is made as follows:--First
release the screw 14 on cross head 13, and while the instrument is
connected up with the air supply, slightly withdraw the trigger 12,
allowing a small amount of air to pass through the nozzle. While
maintaining the trigger in this position, move the cross head along the
needle until it just bears against the cam 10, and in this position
clamp the same by screwing home the clamping screw 14.
[Illustration: Fig. 57.--THE AIROSTYLE PISTOL "M."]
Another important point is to see that the lubrication of the
compressor is carefully watched; the sight feed lubricator on top holds
sufficient lubricant for 10 working days and is capable of adjustment
by means of a needle valve. It can, therefore, be easily set. The main
bearings are ring oiling and only need occasional attention. The fan
bearings are ball bearings and only need attention once in six months.
THE EUREKA SPRAYING MACHINE.
[Illustration: Fig. 58.--THE CRANE "EUREKA."]
[Illustration: Fig. 59.--THE CRANE "RECORD."]
An inspection of Figs. 58 and 59 will show that this machine is of
entirely different construction to those already described. The
advantages claimed are the simplicity in construction, the absence of
complicated parts which might get out of order, and the fact that the
machines cannot clog in use. The operation is as follows: The feed
pipe from air tank should be connected up with a high-pressure hose
to the sprayer and a fluid nozzle is then adjusted so that the tip of
the nozzle is in alignment with the centre of the air nozzle. This
adjustment varies according to the thickness of material. When using
thin liquids the fluid nozzle should be slightly below the centre of
the air nozzle. When ready for spraying the valve is pressed, and
this releases the air, which blows through the air nozzle, across
the top of fluid nozzle and draws up the material from the inside,
spraying the fluid on to the work. The shape of the spray is that of
a fan. The air pressure required varies from 20 to 50 lbs. according
to the viscosity of the material being dealt with. As a rule the best
results are obtained when the machine is held from 4 to 6 in. away
from the work. The Fredk. Crane Chemical Co., Armoury Close, Bordesley
Green, Birmingham, are the agents for these machines, and it is also
manufactured in the United States. The remarks given under the head of
"Exhaust," "Air Compressor," etc., will apply to this machine also.
It may be observed that the cup holding the metal can be very quickly
changed, so that a variety of colours may be sprayed one after the
other with very little trouble. The price of the machine (which may be
provided with an agitator if required) is low.
"THE INVINCIBLE."
These sprayers are designed on an excellent "universal movement"
principle and are particularly well constructed throughout. They
further claim distinction on the score that every section is an
independent unit of standardized pattern, and as spare parts are always
available, replacements and renewals can be made instantly with the
minimum of trouble and cost.
They are made in several types to suit varying classes of work,
ranging from the fine lining and shading of small objects required
by artists, etc., to commercial painting on the scale practised by
motor car manufacturers and other large users; and important points in
their favour are the special facilities provided for quick cleaning
after use, their completely enclosed mechanism, which prevents the
penetration of any dirt, colour or liquid to working parts, and the
adjustment of the needle so that no pressure or damage can occur at any
time to the colour tip, even if trigger is allowed to snap forward.
Automatic control is also provided for work requiring a given volume
of colour, it being only necessary to turn a regulator to ensure a
constant flow of any desired density.
The "Invincible" Pistol Sprayer type "E" is illustrated in section
(Fig. 60). The body is gun metal with working parts of finest steel,
highly polished where necessary to ensure smooth working and minimum of
wear. The instruments have a handsomely nickelled finish.
WORKING.--When connector (4) is attached to colour cup or extension
cock for paint pot and connector (18) affixed to air-line, the air
brush is ready to commence work.
DUSTING.--No separate or special dusting attachment is necessary with
the "Invincible" apparatus, as a slight pull on trigger (20) carries
back steel sleeve (7), depressing steel ball (15) and bringing the air
valve (19) into "open" position. This allows a stream of air to pass
forward through air channel (21) to nozzle (1) and the projection of
this upon surface to be treated removes all dust.
[Illustration: Fig. 60.--INVINCIBLE SPRAYER TYPE "E" IN SECTION.]
SPRAYING.--A continuation of the trigger pull carries back the spring
buffer (8) and opens the control barrel (11) of the needle valve (3)
allowing colour to flow through colour tip (2), at the end of which
it meets the vacuum created by the air stream, and is then (atomized)
broken up into thousands of minute particles which coalesce upon
meeting their object, and form a perfectly level, smooth and even
surface.
CONTROL.--The trigger control is very sensitive, giving a spraying
range from a fine line to the fullest flush of the instrument's
capacity. For automatic control it is only necessary to adjust
regulator (No. 14).
[Illustration: Fig. 61.]
CLEANING.--By unscrewing union nut (5) the complete fore-part may be
removed for cleaning without interfering with any other part of the
mechanism, therefore the operation of cleaning is always quick and
thorough, even when sticky, heavy liquids have been used.
The movement for the above sprayer applies to all "Invincible"
sprayers. Type "A" for artists, miniature tinting, black and white
process work, etc. Type "B" for Christmas and show card work, etc. Type
"C" for ceramic work, posters and so on.
A cheaper series is also made which, whilst lacking some of the
refinements of the standard models, are reliable, and soundly made
instruments.
The patentees and manufacturers of "Invincible" Air Brushes are the Air
Brush Manufacturing Co., Ltd., Pneumatic Works, 13, Arlington Street,
Rosebery Avenue, London, E.C., who also provide all accessories for
complete spraying installation, such as air-compressors, air-receivers,
air valves, reducing valves, condensers and clarifiers, pressure
paint pots and paint pot stands, exhaust benches, fans, turn-tables,
automatic cut-outs, motors, etc., of which complete details will be
sent upon request.
THE MIDLAND SPRAYER.
[Illustration: Fig. 65.--THE MIDLAND SPRAYER.]
From what has already been said, it will be obvious that the most
important part of a spraying plant is the correct construction of the
actual sprayer or spraying pistol. The Midland Fan Co., Ltd., of 46,
Aston Road, Birmingham, have placed on the market a sprayer which
is shown in Fig. 65, and this, we learn, has given a great deal of
satisfaction. Its principal claim to superiority is the simplicity of
construction, for one reason because the sprayer may be used by those
who have but little knowledge of mechanics. The construction permits of
easy cleaning, which is of vital importance, and for this purpose the
needle can be removed by a turn of the fingers and replaced with equal
ease. The illustration shows the larger pistol, and it may be mentioned
that smaller sizes are made for finer work.
THE PAASCHE AIR BRUSH.
[Illustration: Fig. 66.--THE "PAASCHE" SPRAYER.]
This spraying machine is manufactured by the Paasche Air Brush Co.,
9, South Clinton Street, Chicago, in various sizes, for spraying by
compression air liquids of all kinds. The above illustration shows what
is known as the "Three in One" quick action model "S" brush, and is
recommended for use with heavy material. Instead of the paint pot being
at the top an underslung jar with aluminium cover as shown on the lower
part of Fig. 67 may be used. This figure shows the same air brush or
sprayer with one gallon container; in either case the spraying of the
colour or material is quickly done. The flow of the liquid is entirely
independent of the air circulation. An agitator is provided to keep
the material well stirred, and should be used with all liquids which
have a tendency to settle, such as bronzes, enamels, paints, etc. The
coupling or taper stem of the flexible metal tube or bottles are easily
detachable, and one material after the other can be used without
stopping. If the underslung jar or the gravity pot be used no agitator
is necessary.
This instrument is made in much larger sizes. The general form of
apparatus is shown in Fig. 68, the special finishing hood with exhaust
fan being in this case employed, while a paint container is suspended
on an adjustable stand. In this case a chair is shown being painted.
[Illustration: Fig. 67.--LARGER SIZE "PAASCHE."]
A somewhat novel apparatus for separating oil and water is that shown
in Fig. 69. This is constructed to obviate the trouble which is
sometimes caused by the oil and water in the air main mixing. It is
connected at the end of the air main as close to the air regulator
or air outlet to the brush as convenient. Oil gets into the air main
through the piston of the compressor, and will in time saturate the
walls of the air pipes. The condensation of water which is due to
changes of temperature makes the iron pipes sweat, and a considerable
amount of water is accumulated in this manner. The simple appliance
shown in the illustration will remove this.
Fig. 70 shows the Paasche Automatic electric controller which is used
for automatic starting and stopping motor driven compressor outfits
where from 1/8th to 1 horse-power motors are used.
[Illustration: Fig. 68.--GENERAL FORM OF "PAASCHE" SPRAYER.]
[Illustration: Fig. 69.--"PAASCHE" OIL AND WATER SEPARATOR.]
[Illustration: Fig. 70.--"PAASCHE" AUTOMATIC ELECTRIC CONTROLLER.]
CHAPTER VII.
SUPPLY OF COMPRESSED AIR--PAINT SUPPLY--EXHAUST.
The forms of spraying apparatus having been selected, consideration
must next be given to the following details, viz.:--(1) The supply and
degree of pressure of the compressed air. (2) The form and location of
the paint supply. (3) The arrangement of an exhaust installation to
carry away the fumes and waste paint. These will be dealt with in their
order.
It is clear that attention has to be paid to a convenient arrangement
of reducing valves controlling the pressure of air to the sprayer, and
also providing, what is in many cases indispensable, a pressure feed of
colour to the sprayer, either from a large pot mounted over the hood,
or a special type of bowl screwed on to the sprayer.
Some makers still advocate a simple type with small bowl screwed on to
the sprayer, and no means of controlling the pressure save by adjusting
the safety valve on the main tank, thus necessitating that each
operator shall work at the same pressure, arguing that reducing valves,
pressure feeds, etc., etc., are unnecessary refinements, but it may be
safely claimed that such opinions are made without due consideration of
the advantages of the more complete system, and that the consensus of
opinion is in favour of such refinements, giving, as they undoubtedly
do, a further increase in speed, and, in many cases, making practicable
what would otherwise be impossible, as well as ensuring that whatever
work is to be done, the most suitable pressure is instantly available.
In the equipment of an efficient compressed air plant for painting,
the type of compressor employed, and the arrangement of the air main,
should first be decided upon.
The compressors must be designed to give an absolutely pure supply of
air free from oil or grit, and the air-main must be so arranged as
to avoid any trouble due to condensation. This is overcome, first,
by using, at least for high-class work, a horizontal air compressor,
water cooled, with a sensitive sight-feed needle valve lubricator to
the cylinder, capable of delicate adjustment, so as to avoid excess
of lubrication. Needless to say, the machining of the cylinder,
piston, etc., of the compressor must be of the highest class to ensure
satisfactory running under such conditions. Then a suitable air filter
must be fitted to the intake of the compressor. This filter should be
of large diameter, and have a gauze screen and wad of cotton wool.
The air valves should be so arranged that they may be removed without
breaking the water joint, and be so arranged that they may be taken out
and replaced in a few seconds.
The main tank must be provided with safety valve drain cock and
pressure gauge, and the air main, of not less than ¾ in. diameter
barrel, preferably steam barrel, must be arranged to travel in a
downward direction from the main tank towards an end station tank,
which is a duplicate in miniature of the main tank or receiver. All
branches must be taken upwards off the main. Such an arrangement, if
care is taken that the end station tank has its relief valve set to
blow off before the main tank safety valve acts, ensures that all
moisture is collected in the end station tank.
The Airostyle and Lithos, Ltd., claim to be the originators of such a
system, and it is here explained in print for the first time.
All experiments with a view to scrubbing or purifying the compressed
air of moisture, oils, etc., on the air main side of the main tank,
other than the above simple expedient, have proved more or less
failures, either from want of appreciation of the increased capillary
attraction set up in the tanks and air main, or from the difficulty
of satisfactorily and frequently cleaning out such scrubber as may be
inserted, and the incidental difficulty created in the prevention of
dust being carried out of the scrubber throughout the system.
It need hardly be said that ample air must be provided in order
to have sufficient pressure always available for the full number
of operators employed, and this point is one which cannot be too
strongly emphasized, for in too many cases firms have installed small
compressors and have been misled as to their maximum capacity, mainly
through over anxiety on the part of the salesman to secure his order
for apparatus, he apparently having been afraid to ask a high figure
for a really efficient compressor.
[Illustration: Fig. 71.--AIROSTYLE AIR COMPRESSOR. [CAPACITY 40 CUBIC
FEET PER MINUTE.]]
[Illustration: Fig. 72.]
[Illustration: Fig. 73.]
[Illustration: Fig. 74.--DEVILBISS AIR COMPRESSOR.]
Another point of importance is that unloading devices, cutting in and
out automatically should be avoided at all cost where compressed air is
to be used for painting. The reasons are that it is much better to use
the surplus air for the purpose of getting rid of the condensation in
the way already indicated, and that in addition most unloading devices
are in the nature of compromises, and while saving only a small amount
of power materially increase the wear and tear by throwing the load
in the reverse direction on the gudgeon pin, large and small end of
connecting rod and main bearings, and by causing a hammering action to
be set up.
This applies in particular to air compressors with automatic valves
where the device works by means of a valve closing the air intake
entirely, and so setting up a vacuum in the cylinder.
A much better plan is to arrange the compressor to run at a speed
sufficient to give a slight reserve of air above what is needed and to
have it running constantly during the whole working period.
This may seem at first sight an arbitrary attitude to take up, but it
is the result of considerable experience, and need not be considered as
extravagant when it is borne in mind that air compressors of more than
40 to 50 cubic feet per minute capacity are seldom employed for such
work, and so the maximum power absorbed is light.
The compressor illustrated in Fig. 71 is designed and made by the
Airostyle and Lithos, Ltd., and has a number of well thought out
refinements, both as to accessibility and form of valve bodies and
valves, and also with regard to the filtration of the air and the
lubrication of the cylinder. Ring oiler bearings are employed for the
crankshaft, and the compressor throughout is as carefully built as a
gas engine. The makers claim that an absolutely pure supply of air is
delivered by this compressor at all speeds up to 350 r.p.m.
Water cooling is employed and very ample cooling surface is provided,
not only for the cylinder but also the cylinder cover is cooled, and
has the valves located in pockets in same.
An air compressor is shown in Fig. 72, and another one, which is water
cooled, in Fig. 73. These are made by the DeVilbiss Co.
In Fig. 74 are illustrated various forms of air compressors; a pressure
gauge, safety valve and drain cock are furnished with each receiver.
These tanks have welded seams and are tested to 200 lbs. pressure.
[Illustration: Fig. 75.--AEROGRAPH AIR PUMP AND TANK COMBINED.]
[Illustration: Fig. 76.--THE AEROGRAPH TYPE OF AIR PUMP FOR LARGER
INSTALLATIONS.]
One of the Aerograph types of power pump and tank is shown below. It
is strongly built, easy working, and is fitted with metal extending
rings and metal valves, which will supply enough air for three spraying
painters. In the illustration is shown the pump fitted with an
automatic regulator, but this may be dispensed with if desired. The
regulator, therefore, will be found of great value, not only in saving
power, but also in the wear and tear of the pump. The tank is fitted
with an air gauge and a speed valve, and the dimensions of the air
receiver are 18 inches diameter by 30 inches high, and the pump has a
bore of 3 in. while the stroke is 7 in. The power required is 1 h.p.
[Illustration: Fig. 77.--THE AIROSTYLE PLANT--GENERAL ARRANGEMENT OF
ACCESSORIES.]
THE SUPPLY OF PAINT.
For lacquering or coating small articles a spray may be used which is
constructed with a cup to contain the paint, but for any heavy painting
where large surfaces are to be covered quickly a cup on the handpiece
is not of much utility, and it is necessary to provide a means to keep
the supply of paint to the handpiece continuous. This is done in two
ways: By an overhead paint pot, allowing gravity to carry the paint to
the handpiece, or by an enclosed paint pot with a regulating valve and
pressure applied to the surface of the paint by compressed air. In some
situations all that is required is an overhead paint pot, the weight
of the liquid feeding it to the handpiece. An enclosed paint pot has
the very great advantage that (with a proper valve) the feed of the
paint can be regulated to a nice degree. The paint pot shown in Fig.
77 has a damped cover which is capable of being quickly removed, and a
low-pressure feed to the paint is obtained from a reducing valve. This
can be set so that the paint can be forced to the handpiece to secure a
uniform flow whether the paint be thick or thin.
THE EXHAUST INSTALLATION.
We next reach the question of arranging a satisfactory form of exhaust
installation, which has been found to be absolutely essential in order
to insure the health of the operator.
This exhaust question obviously opened up special problems in the
direction of convenient forms of hoods or work benches, so arranged as
to carry away the fumes created by the paint distributor without unduly
inconveniencing the operator by reason of the draught set up.
By some firms use is made of the exhaust to collect the residue or
surplus paint drawn off by employing a ventilator, which sets up a
medium pressure, and interposing between the outlets of the hood and
the air shaft some form of perforated screen or screens which are
readily removable, or in some cases revolvable and self-cleaning.
Where slow drying japans are employed, such saving is of considerable
advantage, although it must not thereby be assumed that an extravagant
wastage of paint occurs, for it must be borne in mind that with a
spraying plant there is no loss through evaporation from open pots and
gradual drying up of the paint on the sides of the pots, or absorption
of same in the brushes employed. Actually, therefore, although it
would appear that considerable wastage occurs, yet in practice it is
found to be economical, and even where intricate forms, such as cycle
frames, wheels, carriers, etc., or bedstead work are to be dealt with
no undue loss is experienced, and such small loss as may be noted is
compensated for ten times over in the saving of time effected.
When selecting a ventilator for the plant, the fact must not be
overlooked that the fine particles of paint, etc., drawn off by
the ventilator gradually coat the blades of the fan, sufficiently
to materially increase the friction, and to absolutely prevent the
exhausting of the air should multiple bladed fans be adopted.
Experience has shown, therefore, that for such work as compressed air
painting multiple bladed fans are to be avoided, even though these are
scientifically designed and admirable for many classes of exhaust work.
Not more than 8 to 10 blades should be employed, and there must be
no belt-drive taken through the air shaft, this being a source of
continual annoyance in addition to creating a loss of efficiency.
Where simple impellor fans are used, long spindles should be employed
permitting an outside drive, but a better type of fan is the central
draught type, preferably ball bearing, as these run for years with
no attention save occasionally filling up with grease and periodical
cleaning.
It may be argued that many of the foregoing remarks are not properly
within the scope of this book, yet on further consideration it must be
conceded that they all have a bearing upon the ultimate efficiency of
the installation, and are the outcome of years of experience.
When arranging a compressed air painting plant considerable thought
must be given to the most convenient position, and where stoves for
artificially drying on the paint, japan, etc., are employed, care must
be taken that a sufficient number of these stoves are provided to give
the plant full scope, for a very material saving per annum is effected,
additional to that accruing through the labour-saving effect of the
apparatus, by the fact that the stoves are filled more quickly.
Where bulky work is to be handled, the plant must be so arranged as to
give ample room for getting the work to and from the hoods.
The volume of exhaust air will depend on the character of the paint
and the size of the cabinet. For large articles a large cabinet is
required, and a proportionately larger fan will be needed. From 500 to
1,000 cubic feet of air per minute should be supplied for each worker.
A hurricane of air is not required; all that is needed is to keep the
air moving away from the worker, and the ordinary type of wall fan may
be sufficient for a simple installation, but cannot be used for large
plants.
AIROSTYLE CENTRAL DRAUGHT STEEL PLATE FAN.
This fan is designed and made by the Airostyle and Lithos, Ltd., and
is invariably specified in all their medium and large installations
for compressed air painting. It is very carefully designed and built
specially for the work, and is fitted with ball-bearings.
As will be seen from the illustration, Fig. 79, it is worth serious
attention on the part of intending users.
It is made in many sizes, from 2,000 to 23,000 cubic feet capacity,
and is very largely used, not only for Airostyle plants, but also for
general ventilation work.
[Illustration: Fig. 78.--THE PAASCHE MOTOR DRIVEN FAN.]
In the above figure is shown a motor-driven propeller fan manufactured
by the Paasche Air Brush Co. It is made in various sizes, varying in
air delivery from 1,200 to 10,000 cubic feet per minute.
[Illustration: Fig. 79.--THE AIROSTYLE CENTRE DRAUGHT STEEL PLATE FAN.]
[Illustration: Fig. 80.--THE DEVILBISS AUTO COOL ELECTRIC EXHAUST FAN,
CLOSED, AND OPEN FOR CLEANING.]
LOCATION OF THE WORK CABINETS.
[Illustration: Fig. 81.--SKETCH OF SPRAYING CABINETS, SHOWING SIDE
LIGHTING.]
As to the position of the spraying benches, it is a little curious
to note that in not a few cases these cabinets are placed facing the
window, the idea being to obtain as much light as possible for the
process. A moment's consideration, however, will show that this is not
the correct position, because the workman faces the light, which is
thrown on the back of the article he is spraying, in exactly the wrong
position for his purpose. The cabinets should be lighted from the back
of the workman and be, as far as possible, directed from the roof or
the top of the room, so that it comes directly on the article to be
sprayed. Clearly it is necessary to provide as good a light as possible
in order that no part of the work shall be missed.
Artificial light will, as a rule, be provided for working on dark days
and after the sun sets, and here again the same provision must be made.
Plenty of light arranged in such a manner that it is directed on the
front of the object to be painted is essential in every case.
After due provision has been made for a suitable exhaust, which
question should be left in the hands of the specialist in compressed
air painting if satisfaction is to be guaranteed, other questions need
attention, such as provision of means for handling the work, special
turn-tables, which should be ball-bearing, if possible, to ensure
light running and enable even heavy articles to be turned about when
spraying, and when examining the work.
[Illustration: Fig. 82.--"AEROGRAPH" SPRAYING CABINETS.]
THE FUMEXER.
In connection with the Aeron, the makers supply a special form of
cabinet or booth, made of steel, which is called by them the "Fumexer,"
and is illustrated in Figs 83 to 89.
These are made in various sizes, from 3 feet to 16 feet wide, and
4 feet to 18 feet deep. They are each fitted with turn-table and
specially constructed fans for drawing out the air, and with it the
superfluous paint, enamel, etc.
Fig. 84 shows a side view of an 8-ft. Fumexer indicating the style of
construction and funnel-shaped back clear to the floor.
The steel Fumexer with the Autocool electric exhaust fan installed
is claimed to insure a maximum exhaust efficiency, and to completely
remove all fumes arising from the work in the finishing room--at a
minimum of power consumption.
The Fumexer is a fire-proof steel booth specially designed and built
for the height of service. It is constructed of heavy sheet steel on an
angle iron frame, with wire glass windows in sides and top. Provision
is made for electric lights--reflector and sockets being built in.
The back of the Fumexer is funnel-shaped clear to the floor, which
arrangement, together with the large fan opening, gives maximum
exhausting results, especially on large work. The short exhaust pipe
running from the back opening is easy to clean and permits of the
placing of the Fumexer near outside wall.
To take care of all classes and styles of work, the Fumexer is
regularly made in a variety of sizes as above mentioned with the proper
number of fans installed. Other sizes to meet any special requirements
are made to order.
A turn-table, which is adjustable, tilting and revolving--either
floor or suspended type--is supplied with the Fumexer. This device
facilitates the handling of a large percentage of work. The floor type
turn-table is not fastened to the floor nor Fumexer and can be removed
when not required.
The Autocool electric exhaust fan installed in all Fumexers is an
exclusive Aeron system product, and is particularly adapted to the work
required of it.
In Fig. 85 is illustrated the side and front views of a 4-foot single
exhaust fan installation Fumexer with suspended type turn-table.
The fan motor, completely enclosed and protected from fumes, is
automatically cooled by a stream of pure air which is continuously
drawn through the motor. This means a fan of increased efficiency.
The motor is only one-twelfth H.P. and will do the required work at
one-tenth or less the power consumption of other styles of exhausting
methods.
Autocool fans are made in one size only, the number of fan units being
increased for Fumexers above five feet in width. In this way the right
number can easily be adapted to any kind of work. The makers claim
that by this arrangement a better distribution of exhaust is obtained,
and the vapour is moved quickly at low pressure through the large fan
openings--this accounting for the small amount of power used.
The next illustration shows the Autocool electric exhaust fan both
closed for use and with motor and blades swung inward for cleaning.
In Fig. 86 is shown a special Fumexer with three exhaust fan
installation and automobile body.
This equipment, together with type D Aeron with V spray head or type
M Aeron with V-A spray head and the air transformer set, is used for
priming and surfacing automobile bodies.
Two very interesting illustrations are Fig. 88, the one on the left
being a Fumexer with automatic elevating and revolving turn-table,
while that on the right is a Fumexer with wheel-jack.
The turn-table is revolved by a 1/8 H.P. electric motor, furnished
in either direct or alternating current. The speed of rotation is
adjustable through a wide range by means of a friction wheel and disc.
The table is started and stopped by either hand lever or foot pedal
entirely independent of motor.
A ten-inch elevation of the table is accomplished by compressed air
acting on a piston which supports the revolving parts. A hand lever
controls this feature, and the speed of elevation and lowering is
adjustable for different classes of work.
This turn-table is especially designed for handling box-like work,
finished inside and outside in the same or different materials. The
elevation feature makes possible the painting of an article one colour
inside and another outside in one operation without interference. It is
also well adapted for use on other classes of small work.
The Fumexer in operation is shown in Fig. 89.
[Illustration: Fig. 83.]
[Illustration: Fig. 84.]
[Illustration: Fig. 85.]
[Illustration: Fig. 86.]
THE DEVILBISS "FUMEXER" OR SPRAYING CABINET.
ACCESSORIES.
It is difficult to classify accessories as readily as the sprayers
themselves; we must content ourselves with a description of some of
these as supplied by the firms mentioned in the previous chapter.
One of the most complete plant supplied is that installed by the
Airostyle & Lithos, Ltd.
They have, in addition to the sprayers, a system of carrying a
specially designed colour pot on a bracket over the hood clearly seen
in Fig. 77. Such a colour pot has a clamped cover, making an airtight
joint, and so arranged as to be readily taken off for cleaning or
re-charging, and with a spun copper container, offering no obstruction
to the flow of the paint and reducing loss to a minimum. Connections
are provided on the top for the pressure feed, for filling up by means
of a funnel, and for permitting the use of the compressed air as a
means of driving out the paint from the flexible tube before leaving
the instrument after work is finished each night.
Another accessory is a smaller pressure bowl made to screw directly
on the pistol sprayer and designed to make possible the use of many
coloured enamels, while still retaining the advantage of the pressure
feed. Pressure is conveyed into the bowl through a flexible tube from a
special type of reducing valve, shown in Fig. 77.
This illustration shows the connections as universally employed on
Airostyle plants.
The reducing valves are so designed as to give in case of the top valve
a pressure up to 15 lbs. for the pressure feed, and in the lower one
any pressure instantly from atmospheric pressure up to the maximum.
It is the practice to take the air pressure from the air main through
the reducing valve into the low pressure tank, as shown, as this
further ensures that absolutely pure air shall be delivered to the
sprayer and a steady supply of air at any pressure is always available.
The low pressure tank is, as shown, a very simple type, albeit soundly
made, and a drain tap is provided at the base of same.
Last, but not least, comes the type of flexible tubing employed,
and this is the outcome of much experimenting, in that the same is
unaffected by the action of turpentine, white spirit, or even naphtha.
Before leaving this question the reader is referred to the numerous
illustrations (see pages 155 to 185), as these give a far better idea
of the completeness of the Airostyle plants than is possible in this
chapter.
TURN-TABLES.
To facilitate handling of goods to be sprayed, a turn-table is usually
found of considerable service. These turn-tables vary according to the
class of work that is being dealt with. In Fig. 87 is shown one made by
the Aerograph Co., Ltd., which is 20 inches in diameter by 12 inches
high. It is made entirely of cast iron, excepting the cone seated
bearing, which is of hardened steel, which rotates freely and is nicely
finished. The weight is 98 lbs. Sometimes turn-tables are provided with
projecting points to prevent the article being sprayed from moving,
while in other cases the top of the table is provided with ridges for
the same purpose.
In all small turn-tables a conical bearing of hardened steel, properly
lubricated, is sufficient for the purpose, but in the larger work it
is desirable to employ ball-bearings. Whichever method is used, it is
essential that the table turns very freely so that it can be moved
almost with a touch.
[Illustration: Fig. 87.--AEROGRAPH TURN-TABLE.]
[Illustration: Fig. 88.--TWO FORMS OF FUMEXER]
[Illustration: Fig. 89.--THE FUMEXER IN USE.]
[Illustration: Fig. 90.--A PAASCHE TURN-TABLE.]
Fig. 90 shows the Paasche turn-table, which can be raised or lowered
into suitable positions as well as tilted at any angle. It revolves
freely with a gentle touch. Larger sizes are supplied. The necessity of
providing for carrying off the fumes which arise in paint spraying has
already been dealt with.
THE AUTO-ELECTRIC AIR HEATER.
This invention is the property of the DeVilbiss Manufacturing Company,
and is intended to overcome the tendency of the air to cool as it
leaves the nozzle in spraying, while it tends to keep it heated till
it reaches the work. It also raises the temperature of the varnish or
enamel, producing a smooth, even finish.
In addition to heating the air, the auto-heater warms the nozzle,
thereby raising the temperature of the varnish. Because of the heated
air and warmed material there is a complete elimination of the pitted,
pebbled or mottled effect so noticeable when "short oil," quick setting
or heavy bodied varnishes or enamels are sprayed on flat surfaces.
The auto-heater enables Aeron users to improve the quality of many
classes of work--in many instances it opens up an entirely new field of
usefulness. The auto-heater and the air transformer set together insure
clean, dry and warm air at the proper pressure, which is an important
factor in the production of the best Aeron results.
The auto-heater applies the heat at the last possible point before the
air enters the Aeron; as a consequence there is absolutely no loss or
waste of heat, as would be the case if the air were heated at some
other point and then passed through the hose to the machine. It is very
easy to understand that if air heated before entering the hose retained
sufficient heat to be of service when reaching the nozzle, it would be
so hot that it would destroy the hose. In the only practical way, the
auto-heater maintains the heat in the air at the proper degree till the
spray reaches the work.
The auto-heater is light, yet rugged in construction. It has no
exposed contacts. The conductor wires run through the air hose. It
can be attached to any style of Aeron without difficulty. There is
an automatic cut-off furnished with every auto-heater. Placing the
Aeron in the cup holder, or hanging it on the hook, automatically
cuts off the current--picking up the Aeron automatically turns on the
current. This automatic control effects a great saving in current.
As a protection against overheating the auto-heater is equipped with
a fusible safety disc, which melts, allowing the air to escape, if
current is left turned on by accident when the Aeron is not in use.
This safety device operates within four minutes. Several extra discs
are furnished with every outfit. The auto-heater can be connected to
any electric light socket, and consumes only 250 watts current when in
operation.
The construction of the auto-heater will be understood on reference to
Fig. 91.
Another interesting heater is supplied by the Airostyle & Lithos, Ltd.,
a number of which are in use in this country Its general form can be
seen on reference to Fig. 102, page. 165, which shows a gas-heated
type. The same heater is also supplied either electrically or steam
heated.
In all types it has the same general features, namely, a water-jacketed
colour pot, a special coil for heating the air supply, which is
afterwards passed through the water jacket for the dual purpose
of raising the temperature of the jacket and damping down the air
temperature at the same time. To a convenient standpipe the hot air is
carried and distributed to the pistol, and also to a special jacket
round the colour tube.
The Airostyle pistol is provided with an adjustment which admits of the
hot air by-passing the whole time so, maintaining the pistol at the
same temperature as the colour pot and ensuring a steady flow of the
japan.
The heaters are mounted on a stand at the side of the hood and are
complete with pressure gauges, regulating valves, special burner for
gas, or an electrically heated pot giving three heats, or for steam
giving a wide range of temperatures controlled by the steam pressure
through a reducing valve. It must be explained that the same result is
obtained no matter which form of heater is employed, and that in no
case can the japan be burnt. The heaters are used for thick black tar
varnish, or cycle japans, also for certain gum or glue mixtures and
special varnishes.
[Illustration: Fig. 91.--THE AUTO ELECTRIC AIR HEATER.]
CHAPTER VIII.
STENCILS AND MASKS--THE REQUIREMENTS OF DIFFERENT TRADES IN SPRAYING.
Just as in applying paint by immersion some parts which are not
required to be painted can be protected, as already explained, so in
spraying.
Certain parts are to be left unpainted, such as the plated fronts
and glass lenses of cycle lamps. This is effected by the adoption of
some system of masking. Such masks are, however, very simple and are
sprung on with a simple wire spring or clip, and so held in place while
spraying.
A mask has been designed and patented purposely for use when spraying.
This is described on page 143. This mask has embodied in it a plunger
on the end of which is mounted a rubber sucker, and as the plunger is
controlled by a spring, all that is necessary to do is to depress the
plunger down on to the lamp, box, or whatever article is to be painted;
and as the sucker of the plunger comes into contact with the article
first, it grips the surface and the spring behind the plunger forces
the mask, which may be any shape, but is preferably of box form, down
upon the article. This mask is very practical, but its use is limited,
to some extent, to forms of lamps which do not need any stencil or
mask. Such a step, needless to say, has only been taken because the
system of compressed air japanning is the one ideal method--and one has
only to refer to manufacturers who have used it for confirmation of
this.
In addition to simple masks, there are many more complicated forms,
such as those in use in gas meter manufactories, where there are no
fewer than half a dozen points to be masked, and in hardly any case do
more than two points remain the same over numbers of meters to be dealt
with.
However, this has been overcome by arranging the masks on a spring
foundation, and making them capable of sliding adjustment in two or
more directions, and the time taken to fix these masks is in no case
more than 30 seconds. Seeing that the time taken to brush a meter (even
a small one) is not more than seven minutes and the time taken to spray
one, with a superior result, is not more than one minute, there is a
very considerable saving even after allowing time for fixing the mask.
[Illustration: Fig. 92.--MASKS FOR GAS METERS.]
Other stencils are employed for lettering on plates, despatch boxes,
and for ornamental work on cash boxes, etc., and need no further
description here other than stating that these must be of something
stronger than tinfoil, and not too strong to prevent them being pressed
firmly down on to the article to be dealt with.
In other cases, stencils are spun or pressed out to exactly fit the
article, as in the case of brass lacquered goods, rubber balls,
enamelled ironware, etc., and in some cases, where a number of
stencils are employed, for one pattern, these are arranged round a
common centre, and hinged so that, once the article is in position,
stencil after stencil may be readily and accurately brought into
position over the work.
For decorative work, very elaborate stencils are employed, with many
plates for each design; but such stencils hardly come within the scope
of the present work, although they are employed for wallpaper work, and
in the textile industries for high-class effects.
THE HART PATENT MASK.
[Illustration: Fig. 93--THE HART PATENT MASK.]
A very ingeniously constructed, although simple, mask which is suitable
for many purposes, but particularly for motor and carriage lamps,
has been patented by Mr. Walter William Hart, of the firm of Matthew
J. Hart & Sons, Great Barr Street, Birmingham, and others. By this
invention means are provided for applying the mask to a plain surface
so that it may be immovably held without causing injury to the surface.
The mask, too, has the advantage that it can be placed in position with
extreme rapidity. By this invention the mask is fastened in position
by a suction pad, preferably made of indiarubber, which, when pressed
on to the surface to be covered, adheres thereto by the pressure of
the atmosphere. In Fig. 93 is shown an inner face view and a sectional
elevation of the device. The mask (_a_) is adapted to have an axial
movement in relation to the suction pad (_b_) so that when such pad has
been fixed in position the mask may be pressed close upon the surface
it is required to protect. This suction pad (_b_) is of a conical
formation, and is secured to the end of the plunger (_c_) which passes
rearwardly through a hole (_d_) in the back of the mask, and through
a tubular extension (_e_) passing rearwardly from the back of the
mask. The rear end of the plunger has a hole therein, which hole is
screw threaded, and to such end a cap (_f_) is secured. A stud (_f_)
on the interior of the flat end of the cap screwing into the said
tapped hole, and the cylindrical portion (_f2_) of the cap slidingly
fitting over the tubular extension (_e_) on the mask. A spiral spring
(_g_) surrounds the plunger, one end bearing on a shoulder (_h_) at
the rear of the mask and the other end bearing against the cap (_f_).
To fasten the mask, the same is placed in position over the part to be
covered and the cap (_f_) is pressed down, thus pressing the suction
pad (_b_) upon the surface of the article, to which it adheres. A mask
constructed according to this invention is capable of a great variety
of applications, one of which is in connection with lamps. That shown
in the illustration is intended for this purpose.
It will be clear that the shape, however, can be varied according to
the article to be painted by spraying; for example, it may be used with
advantage for decorative purposes.
MAKING STENCILS.
When it is decided to spray through stencils, it is usual to employ
thin copper plates for the purpose, although in wallpaper decoration
very heavy copper stencils are used, because, these being held
horizontally, the weight increases the stiffness of them, while it
prevents them shifting while in use. In ordinary work, however, where
a stencil must be used vertically, the lighter stencil will be most
useful. If paper is used, the best material is Japanese vellum, which
is manufactured from a special fibre and possesses the advantage of
being easy to cut and makes remarkably durable stencils. It is imported
from Japan by Jas. Spicer & Sons, Ltd., 15, Upper Thames Street,
London, E.C. Manilla paper may be had from the same firm, and answers
also very well. For some styles of work, lead foil gives good results.
Messrs. Locke, Lancaster, and W. W. and R. Johnstone & Co., Ltd., 94,
Gracechurch Street, E.C., supply a material which they call "Four-ounce
stencil metal," which weighs 4 ounces to the square foot, is made in
sheets 6ft. by 2ft. 6in., and in smaller sizes, and costs 2s. per
lb. It can be easily cut with a stencil knife, and is most suitable
for work on horizontal surfaces. Another paper which may be used is
ordinary Whatman's paper. The usual method of cutting is to use a very
sharp knife, such as a shoemaker uses, and to cut on a sheet of glass.
If any variety of paper is employed, it will be necessary to apply two
coats of shellac varnish, ordinarily called "Patent Knotting." This
protects the surface of the paper from being worn away by the action of
the brush. Some stencil cutters prefer boiled oil for the purpose.
Zinc stencils are sometimes employed. These may be made as follows:
The thinnest sheets of zinc are employed for the purpose, and upon
this is painted the letters or design to form the stencil. The whole
of the zinc which is not to be cut out, or rather, by this process,
eaten out by acid, must be protected by means of a varnish made as
follows: Take one pint of best asphaltum varnish, two ounces of beeswax
and half-an-ounce of rosin and four ounces of Venice turpentine. Melt
the beeswax and rosin in the Venice turpentine, and while warm add the
asphaltum varnish, mixing thoroughly together. Paint this on the back
of the zinc plate and on all parts that are to be protected. Form a dam
or little wall made of 6 parts of beeswax and one part of tallow melted
together and allow to cool. This is intended to confine the acid to the
parts required to be eaten out. Nitric acid is used for the purpose
mixed with three parts of water. This is poured on the space inside
the dam and allowed to remain on for from 24 to 48 hours, when it will
be found to have eaten away the zinc on the parts unprotected. Further
information concerning stencils will be found in the book entitled
"Stencils and Stencilling," by A. L. Duthie, published by the Trade
Papers Publishing Co., Ltd., 365, Birkbeck Bank Chambers, High Holborn,
London, W.C., price 3s. 3d.
REQUIREMENTS OF SPECIAL TRADES.
The following hints are given of the requirements of a few special
trades:--
_Piece Work._
In very many cases where articles are painted by means of compressed
air it will be found quite practicable to have the work done by piece
work. The exact time taken to spray any particular article can, after
a very little practice, be determined quite accurately. In fixing the
price to be paid for the work an allowance must, of course, be made
for the time taken in bringing the piece to the spraying cabinet and
placing it ready to be taken away by the boys or labourers. It is in
this detail that speed may be increased so materially. The actual time
of spraying to a great extent regulates itself, but if care is not
taken considerable waste of time will be occasioned in getting articles
ready and taking them away, and a satisfactory arrangement of piece
work to both employer and employee will remove this waste of time and
will prove more beneficial than day work.
BOOKBINDING.
The principal use of spraying in this work is to put on the speckled
edges of books after they are sewed and before binding. This is usually
done by splashing colour from a stiff-haired brush over a comb, but
the method is a crude one at best. In using a spray for the purpose
one of the simpler forms will do all that is required. The pressure
must be lowered and paint removed some distance from the books until
the requisite size of the spots or dots of colour is obtained. With a
little practice this can be regulated to a nicety.
CARRIAGES.
The remarks which will be found elsewhere, under the head of
"Tramcars," apply to some extent to carriages also, and although the
superfine finish required for a high-class carriage could hardly be
produced excepting by the old-fashioned means, yet the processes of
flowing-on and spraying could, without doubt, often be employed for the
cheap and moderately cheap style of vehicles of various kinds which are
now produced on so extensive a scale.
CYCLE PARTS.
Many parts of cycles are now painted by means of spraying, although
some firms prefer dipping. Whichever process is used it is necessary,
as a rule, to give at least two or sometimes three or even more coats,
and to get a fine finish to rub down between these coats with powdered
pumice and water, and, for the last coat underneath the finish,
rottenstone and oil. The parts must always be stoved, as air drying
enamels are not, as a rule, sufficiently hard to permit of their
resisting the hard wear to which cycles are subjected. It need hardly
be said that the method of handling various parts will to a great
extent determine the economy effected.
The wearing parts of cycles are sometimes finished in the following
manner, which is the method used by the Birmingham Small Arms Co.
Although somewhat expensive it is certainly worthy of all praise,
because it gives so durable a finish. The iron or steel parts are first
thoroughly washed in American turpentine and are then stoved, the
result being a perfectly clean surface. A coat of Calcutta linseed oil
is then given by means of brushes and the parts are then stoved at 250°
F., after which they receive a coat of what is called "Black Rubber
Solution," an elastic enamel which dries with a semi-gloss. Then two
separate coats of khaki colour japan are given and each are stoved at
280° to 300° F. A little rubbing down between the coats is sometimes
necessary, and this is done with glass paper. The parts thus finished
are very suitable for work which is to be subjected to very hard wear.
At this writing the cycles are all intended for Government, hence the
care taken in the finish.
ELECTRICAL WORK.
Painting by compressed air is done in the case of many parts of
electrical apparatus, the process being similar to that previously
described. Thus the metal work of fuse boxes may be finished in this
way with black japan, and one coat stoved at 250° F. or thereabouts
will usually be found to suffice.
Among the large number of electric works where the process is employed
may be mentioned those of W. T. Henley's Telegraph Works, Ltd., at
Gravesend. The Airostyle is used in this case, and the work is done
approximately from twice to three times as rapidly as it was formerly
done with the brush.
FANCY BASKETS.
Fancy baskets which are made of cane, willow, special straw and other
materials can be sprayed with admirable effect in many cases where
brushing would be impossible. Indeed, the application of a spray in
this work may be considered to have created almost a new industry in
a wide range of fancy goods, which may be sprayed with gold paint,
or a great variety of coloured enamels may also be employed. In this
case celluloid varnishes are also employed with the addition of coal
tar dyes for the production of colours such as mauve, blue, moss
green, rose pink, amber, orange, fire red, navy blue, etc. The work
of spraying in this case is usually done over a bin such as is shown
below, a simple wire device being used at the top to support the basket
while it is being sprayed, although even this is often dispensed with
as the article may be held by the handle, and being very light this is
not found to be irksome.
[Illustration: Fig. 94.--BIN FOR SPRAYING LIGHT ARTICLES.]
GAS METERS.
At the present time less than half a dozen gas meter manufacturers or
repairers have a paint spraying plant in use, and these are described
elsewhere. The saving, however, by spraying the paint is in this class
of work very considerable, amounting to about 1 to 5; that is to say,
five times as much work can be turned out with a spraying machine as by
hand. It is generally recognised that the quality of the painting is
much improved, it being harder and better in appearance and generally
more satisfactory. Turn-tables of a simple character are employed,
and 24 hours are allowed for the drying of the work. For protecting
the indicators, the name of owner or manufacturer and brass plates
of similar character, various types of shields or masks are employed,
consisting of a plate of requisite shape soldered on to a piece of
stiff wire, with turned ends, which embrace the meter and hold it in
position. There appears to be no reason why the larger size gas meters
should not be painted by spraying, provided that a suitable plant,
which would be of a simple character, were provided. There is but
little doubt that in a little time every manufacturer of gas meters
will find it necessary to employ a spraying plant.
GAS STOVES AND RANGES.
In this class of work spraying is used almost exclusively; as only one
side of the iron is to be painted the dipping process is obviously
unsuitable. The work is done at a pressure of about 45 lbs., but
sometimes a little less is sufficient. The usual exhaust is provided
and turn-tables are employed having bearing wheels on the outer edge of
a circular plate. Those used for the larger ranges are usually level
with the floor. In addition to black, all kinds of colours may be used.
This work is mostly done piece work. The smaller parts, such as rings,
cookers, etc., are also sprayed. The stoving is done at 350° F., but
when two coats are given the first is subjected to 450° F.
The interior of the ovens are coated for a finish of oxide of tin,
which when stoved at a high temperature assures a great increase of
"body" or opacity. Sometimes the finish is left solid, but in most
cases the coat is stippled.
The usual overhead runways consisting of hanger on four wheels on
V-shaped girder are employed.
PICTURE FRAMES, PICTURE MOULDING, ETC.
One of the industries in which paint spraying is strikingly successful
is that of preparing picture frames with a "gold" finish. If properly
done the result is even better than if gold leaf is used, as the spray
covers completely the most elaborate and intricate ornament. Picture
frames or mouldings of various shapes and sizes are obtained ready for
receiving the various coats necessary to give a gold finish. Formerly
the whole of the operations were done by means of brushes, but this
method has been wholly superseded by spraying, which approximately does
the work five times as quickly and gives a far better result.
Three separate processes are employed; the first is the application of
a coat of enamel, the second a coat of bronze or "gold paint," and the
third the application of a transparent lacquer. The last protects the
bronze from discoloration, and the manufacturers guarantee that such
mouldings will last at least 5 years without tarnishing.
The whole of the work is air dried, but to facilitate the operation the
workroom is kept at a temperature of about 75°F and the drying ovens
up to, say, 80° or even 85°F. The first coat of enamel is sprayed on,
and in about two hours is felted down with a pad similar to that used
by french polishers. This is dipped in a solvent which removes all
inequalities. The actual spraying is done on a long open trough shaped
bin some 3 ft. 6 in. from the floor having exhausts at the bottom and
thin laths placed across it at intervals of about 18 inches. The long
stretches of moulding are placed on these laths lengthwise, the laths
holding them in position. The spraying is done directly on them and
they are turned from side to side, and when the spraying is completed
each length is lifted bodily by two boys, one at each end, on to racks
in the drying room which is close by and which has a large number of
open iron shelves running from end to end. These shelves are quite
close together, so that a large number of lengths of moulding may be
dealt with at one time. Heat at about 85°F is admitted at the bottom,
and the drying apartment is open from end to end in front so that the
mouldings may be readily introduced. This heat also serves to warm the
room.
The enamel being dry the length is removed and gone over with a pad
as described and the gold paint is then sprayed on over the whole
of the work, giving a beautifully fine and compact gold finish. The
application of the transparent lacquer completes the operation. The
materials used in this work are special spirit varnishes made on
a base of celluloid. The exact composition varies with different
manufacturers, but the following recipes are based on "The Manufacture
of Spirit Varnishes," by Livache and McIntosh (Scott, Greenwood and
Son), and will be useful for reference. The great advantage of using
celluloid is that a coloured transparent varnish is obtained.
RECIPE FOR CELLULOID VARNISH.
1. Celluloid 1 lb.
Amyl Acetate 2 lbs.
Acetone 2 lbs.
Ether (Syph. Meth.) 2 lbs.
2. Same as before with the addition of 1/5th part of
camphor.
3. Celluloid 1 lb.
Amyl Acetate 5 lbs.
Acetone 5 lbs.
Picture frames are also finished in black having a semi-gloss
finish, which gives an excellent effect and is most durable.
It is very important in this class of work that ample ventilation be
given to the apartment in which the work is done in such a way as to
avoid draught. Heated air, of course, takes up moisture much more
readily than cold air, and unless means are provided for adequate
ventilation the air will become moisture charged, and the work will
thereby be adversely affected. This is a point which is frequently
overlooked.
SPRAYING SHIPS' HULLS.
It is the opinion of the author that the painting of ships' hulls may
be done by means of spraying with a great saving of time. Although
there are no available statistics, it is probable that many thousands
of acres of surface on ships' bottoms are re-painted every year. A
careful enquiry has shown that some experiments have been made in this
direction, but that they have always been of a somewhat perfunctory
character. The very large surface gives an opportunity for the use of
the spray which is almost unequalled in its possibilities. There are,
however, certain difficulties in connection with this work, which have
doubtless had much to do with the fact that it has not, thus far, been
adopted to any considerable extent.
The first of these is that the composition applied is not ordinary
paint, but one which is mixed with arsenic, mercury and other poisonous
compounds, which are added in order to destroy animal and vegetable
life and prevent the adhesion of barnacles and other marine growth. So
necessary is this that compositions are made suitable for different
waters through which the vessel must pass, and it is well known that
those vessels which sail by regular routes need much less frequent
painting than a tramp steamer which may sail in any direction and
through any sea. The reason is, that in the first case the composition
is specially made to withstand the growth of life in well-defined
waters, while in the case of tramp steamers it must be more or less of
a general nature.
The point, however, which has now to be dealt with, is that the
addition of arsenic, etc., added to the paint, causes it sometimes to
settle out, but it is suggested that this could be easily overcome
by an agitating apparatus in the paint pot. As explained elsewhere,
such an apparatus is frequently used in ordinary painting, when the
composition of the paint demands it.
The second and more serious objection to spraying ships' hulls is that
the work must be done in the open, and that the wind will carry away
a portion of the paint and prevent it reaching the surface required.
It is suggested, however, this might perhaps be overcome by adopting
a form of enclosed cabinet, which would screen the operator from the
wind. This could be rendered portable by being mounted on a platform
with wheels, and a system of elevators, and be adopted with a little
ingenuity to reach the higher parts of the vessel. In any case, the
subject is one which is well worth the attention of those interested in
spraying, owing to the immense field it opens up.
In this connection attention may be directed to the illustrations which
appear on pages 252 to 254 of the apparatus used for spraying by the
Pennsylvania Railroad for painting their freight cars. This apparatus
may be adapted, with suitable modifications, for ship painting also.
SLATE ENAMELLING.
The usual procedure followed in connection with enamelling on slate for
mantel-pieces, stall-board, signs and other work of the kind, is to
get the slate slabs quite smooth and level by means of a slate planing
machine. A coat of "black varnish" or enamel is then sprayed on, and
is stoved at 160° to 170° F. Careful rubbing down with powdered pumice
and water is next done, when the work receives a second coat of enamel.
It is again stoved and then rubbed down by hand to a finish with
rottenstone and oil. Sometimes, the slate receives three coats, the
finish being left with a high gloss, but more frequently the semi-gloss
obtained by rubbing with rottenstone is preferred. It is unsafe to
stove slate at higher than 260° F., as it is likely to break when
cooling.
Formerly, a great deal of this class of work was done in imitation of
various marbles, mostly worked on a black ground, but "marbling" is
now done but rarely. The method is to employ a shallow tank of water
upon which are placed colours in imitation of the veins of the marble
to be imitated. This colour is of a special kind, made to float, and is
manipulated on the surface. The slab of slate, which has received one
coat, is then dipped gently in the water, when the colour adheres to
it. A coat of stoving varnish completes the operation.
Many slate enamellers still employ the old method of applying the
enamel by means of brushes, but it is only a question of time before
compressed air will be used almost exclusively, for the reason so
frequently urged in this work, viz., that the spray eliminates brush
marks and, therefore, greatly reduces the work of rubbing down.
SPRAYING COLOUR SPECIMENS.
Specimens of various colours in distemper, oil, varnish and enamel are
sent out in very large quantities by the various manufacturers of those
goods, and the preparation of these specimens may be very considerably
facilitated by using a suitable spraying machine. When distemper is
used fairly large sheets of paper are usually employed, and these are
cut up by means of a guillotine machine when dry. Ordinary oil paint
and varnish paints may in like manner be sprayed, but when an enamel
finish is desired it is usual to apply the paint on the back of a sheet
of thin white celluloid, which gives the appearance which would be
obtained by the application of varnish. In spraying celluloid sheets
it will be found that after a little practice the paint may be laid
on much more uniformly than is possible by means of a brush. This can
easily be demonstrated by holding up the painted sheet to the light,
when it will be found that the paint applied by a brush shows more
inequalities or streaks than that when sprayed.
Stencilling may be done very well on either paper or celluloid sheets;
in the case of these specimens, for example, supposing it was desired
that each specimen of colour when cut up should bear a number, it
would not be difficult to cut a stencil in zinc or leadfoil, repeating
the number as many times as there are specimens to be cut out of each
sheet. The tinfoil would then be fixed in position and the spraying
done over it, which would mark each piece with a number. Then the coat
of colour can be sprayed all over the surface. The plan above would be
followed in the case of celluloid, but when ordinary paper is used the
process would, of course, have to be reversed and the number put on
last.
In some cases where a very great brilliancy of colour is required,
this is done by the process of glazing, which is described elsewhere
in this book; for example, a comparatively dull red could be very much
brightened by spraying a coat of madder or crimson lake. Here, again,
if celluloid is used the glazing colour will go on first and the ground
colour afterwards, but in ordinary circumstances the ground work would,
of course, be first applied.
Probably the most complete plant for preparing colour specimens is
in use by Mander Brothers, the well-known paint, varnish and colour
manufacturers, of Wolverhampton. The spraying of colours is mostly done
on celluloid sheets, and four cabinets of the Airostyle type are in
more or less constant use. These cabinets have glass sides and top hung
on hinges so that they may be opened when desired. The pressure of air
is usually from 30 to 35 lbs., with an additional 5 lbs. on the paint
pot. One coat is sufficient, because, of course, it can be made as
thick as may be necessary according to the particular specimens being
prepared. The saving of time is estimated at, at least, 33 per cent.
In dealing with celluloid sheets it is obviously of importance to adopt
some safe means of storing them while drying. Formerly Messrs. Mander
Brothers had a long series of double clips by which the sheets were
suspended while drying, but this method has been abandoned owing to the
danger involved of fire. Now suitable tin-lined cabinets are provided
having from top to bottom a series of cleats which support open wire
trays. Each sheet of celluloid as it is painted is placed on a wire
tray which is slipped in the cabinet, where it dries in 12 hours.
TRAMCARS.
[Illustration: Fig. 95.--GENERAL VIEW OF AIROSTYLE PLANT FOR 16
OPERATORS ON SMALL WORK.]
[Illustration: Fig. 96--VIEW OF AIROSTYLE PLANT FOR 16 OPERATORS,
SHOWING VENTILATOR.]
As far as the author can gather information, the processes described
in this book are not used in Great Britain to any extent in the finish
of tramcars, but are gradually making headway in America, particularly
for the final coats. There appears to be no reason, however, why
"flowing-on," as described in Chapter XIII., should not be used to a
much greater extent than is at present the case. The earlier coats,
being very stiff, might be applied by means of brushes, and these
coats could be followed by spraying, and finally the finishing coats
could be flowed on.
Formerly, this work was done almost in the same way as that by which
the fine finish of a carriage body is produced, viz., the building up
of a perfectly smooth surface by a large number of coats, rubbing each
one down carefully and finishing with two or more coats of varnish,
these being also rubbed down excepting the last.
In modern practice these methods are greatly simplified, and at least
several coats, which were formerly thought to be necessary, are
dispensed with. The finish is often obtained by applying a coat of a
suitable enamel, rubbing this down, and then giving a final finish of a
good flowing varnish.
It is suggested that spraying, or flowing-on, could be used for some of
this work with very great advantage in the saving of time.
In dealing with many paints which are to be stoved, a well-thought-out
system should be in use of conveying the articles from the finishing
rooms to the painting apparatus and thence to the ovens. If more than
one coat is given it will be necessary to arrange also for conveyance
after the parts are baked back to the painting plant for the next coat.
As a rule, a system of overhead runways, such as is described for use
in paint dipping, will be found the most economical method to adopt.
It will be observed that in the list of trades and articles which
may be successfully painted by mechanical means, given on pages 3 to
6, there are many which are omitted from the detailed descriptions.
The reason for this is that the main principles are in all cases
practically the same and the details must necessarily vary, not only
with the goods being dealt with, but according to the extent of the
operations and the accommodation of the factory available.
Thornley & Knight, Ltd., of Birmingham, specialise in this business,
and have sold, during the last few years, many thousands of gallons of
their air-drying coloured japans, for use on car bodies. Many of the
largest motor car manufacturers have adopted the process.
CHAPTER IX.
SOME TYPICAL PLANTS.
An interesting Airostyle plant is shown in Figs. 95, 96 and 101, and is
arranged for 16 operators to deal mainly with bronze lacquers, hence
the somewhat simple arrangement with no provision for adjustment of
pressures at each hood.
[Illustration: Fig. 97.--SIDE ELEVATION OF PLANT FOR 12 OPERATORS.]
It will be noted that the ventilator employed is of important size; the
compressor delivering air to the plant is stationed in the basement.
The views of the plant are excellent, and serve to remove the erroneous
impression that such a plant cannot be conveniently and economically
arranged, both as regards floor space occupied and the provision of
adequate gangways on all sides.
Another interesting Airostyle plant is shown in Figs. 84, 85 and 86,
and was installed for japanning gas fires, radiators, gas cookers,
etc. An item worthy of note in this plant is the patented hot air
apparatus installed for warming the japan and for also heating the
sprayer and flexible tube conveying the japan to the sprayer; it is
clearly seen in the centre of the two hoods. The large hood is mainly
used for radiators, which are wheeled on to the large ball-bearing
turn-table, shown white for the purpose of a clearer view, but when
not so used a table is wheeled into position and two operators are
accommodated for smaller work.
[Illustration: Fig. 98.--PART END ELEVATION OF PLANT FOR 12 OPERATORS.]
The power unit, consisting of electric drive and suitable overhead
countershaft, together with the compressor and ball-bearing fan, is
shown in Fig. 100, and is directly outside the japanning shop.
This plant was installed for the Davis Gas Stove Company, Luton, and
has been in operation for several years.
The compressor shown in Fig 98 also delivers air to the gas cooker
department for two or three operators, and to the porcelain enamelling
department for six or seven operators, but as the same practice is
adopted as is shown in the photos here reproduced, no useful purpose
will be served in describing them in detail.
Undoubtedly one of the most important plants in the country, and one
producing the highest finish, is installed at Messrs. Joseph Lucas,
Ltd., Birmingham, and the photographs reproduced here are by their
kind permission. The author was granted the privilege of inspecting
the plant fully, and proposes to enlarge upon its arrangement and
capacities for saving of labour, etc.
[Illustration: Fig. 99.--PLAN OF FIGS. 96 AND 97.]
The whole of the work was carried out by Messrs. The Airostyle and
Lithos, Ltd., and it must be admitted that the plants are so arranged
as to admit of rapid handling of the work, and the subsequent stoving
of the articles is just as conveniently provided for.
Two distinct plants are in use at the moment with a separate steel
plate central draught fan and a water-cooled air compressor (the type
of fan and air compressor employed is shown elsewhere in the book, see
Figs. 71 and 79).
[Illustration: Fig. 100.--AIROSTYLE PLANT POWER UNIT, COMPRESSOR, MOTOR
FAN ETC., INSTALLED FOR THE DAVIS GAS STOVE CO., LTD., LUTON.]
On referring to the drawings Figs. 97, 98 and 99, showing respectively
an elevation, end view and plan of one of the plants, it will be seen
that the plant is divided up into two bays, each accommodating six
operators, so that, in all, twenty-four operators are provided for in
the two plants and were actually seen at work.
It will at once be noticed that ample space between the bays is
provided, and this is most essential in order to give sufficient room
for the racks which are wheeled into place behind each operator. These
racks are readily seen in the photographs, Figs. 103 and 106, and can
also be distinguished in Fig. 104.
The japanning shop in which the plants are installed is of large
dimensions, 250 feet long by 48 feet wide, and is extremely light and
airy, but, owing to the fact that the roof-lights are now painted
over (by Government regulations), the shop at present appears to
disadvantage, and the photographs consequently suffer.
The photographs, nevertheless, show very clearly what an immense amount
of work can be daily handled, but, notwithstanding this, the writer
was assured that there were still numbers of brush hands in the shop.
This was primarily due to the fact that full arrangements for spraying
are not yet completed (12 more operators are being provided for), and,
secondly, to the fact that certain work needing a large amount of
masking can be almost as readily brushed, and this class of work finds
employment for brush hands. Messrs. Lucas, Ltd., admit that there is a
wastage of japan, but maintain that a heavier and much more even coat
is applied with a superior finish to brush work, and that there is an
enormous gain in time of about 4 to 1 over brushing.
They state, also, that an indirect gain is obtained in the economical
working of the stoves, for these are filled far more quickly, and,
consequently, the daily output per stove is correspondingly increased.
A striking proof of the saving is their statement that if they had
not the system of spraying at work, it would have meant 200 hands in
the japanning department, whereas they now employed only 90, and a
considerable number of these were engaged upon brush work, so that if
only the whole of the work could have been handled with the spray, then
the number of hands necessary would have been even less than 90.
The photographs, Figs. 105 to 107, need no description, and are
self-explanatory to a large extent.
The type of instrument used, and the accessories, are described in
detail elsewhere, as they are the standard practice adopted with all
Airostyle plants.
The writer also had the privilege of inspecting another interesting
Airostyle plant, installed at Messrs. G. Cabdy and Sons, Birmingham,
where 7 or 8 operators are employed upon high-class celluloid enamel
finishes upon buttons, medallions, cameos, electrical fittings,
and last, but not least, numerous parts for munition work, such as
cartridge clips for 18 or 24-pounders, etc.
The small articles are laid on a grid measuring about 11 inches by
9 inches, and while holding the grid the operator sprays over the
whole of the article on the grid, and in the case of rounded faces of
buttons, sprays these obliquely from all sides in turn, as well as over
the tops of the buttons.
It may be mentioned that the greater part of the spraying paints and
enamels are supplied by Messrs. Thornley & Knight, Ltd., of Birmingham.
THE BIRMINGHAM SMALL ARMS CO.
The cycle department of this well-known firm deals with an enormous,
amount of parts, and a new paint spraying department on an extensive
scale is in course of construction at Redditch, and the method in use
at the Birmingham works will be to a great extent followed. In both
cases the "Midland" sprayer is used under a pressure of from 30 to 50
lbs.
The method is very thorough, and although comparitively expensive
is well calculated to produce a finish which is (a) capable of
withstanding hard wear and possible knocks and (b) absolutely
rust-proof. The finish is elastic and very durable. It is produced by
the following method. The steel or iron parts are first thoroughly
washed in pure American turpentine in order to remove every trace of
grease and dirt. In passing, it may be said that a suitable white
spirit would probably answer as well and would effect a considerable
saving, although it is possible that the pure turpentine leaves a
certain residue behind it which is of advantage in forming a key to the
subsequent coats. The parts are then stoved, when a coat of pure Baltic
linseed oil is applied by means of brushes, and they are again stoved
at 250° F. Then a coat of black japan, known in the works as "rubber
solution," is sprayed on, and a third stoving is given in this case at
280° F. This is followed by two coats of khaki-coloured enamel sprayed
on, which dries with a semi-gloss finish. The parts are stoved between
each coat and after the final coat, so that they receive five stovings
altogether.
[Illustration: Fig. 101.--COMPRESSOR, ETC., FOR AIROSTYLE PLANT FOR 16
OPERATORS.]
[Illustration: Fig. 102.--AIROSTYLE PLANT INSTALLED FOR GAS FIRE AND
RADIATOR WORK FOR MESSRS. THE DAVIS GAS STOVE CO., LTD.]
The ovens are of special construction and are described in detail
elsewhere. The japans employed are supplied by Messrs. Arthur Holden
and Co., Ltd., of Birmingham.
Samples of the work thus finished were submitted to the author, who
carefully tested them. He found that the finish was all that could
be desired. A piece of plate metal, for instance, was bent double
without the finish being affected, thus showing very clearly the great
elasticity of the coating--a most important and necessary quality in a
finish for this class of work.
MESSRS. FLETCHER, RUSSELL & CO., LTD.
This well-known firm use spraying at their Warrington Works on an
extensive scale. All parts of gas cookers, gas stoves, and ranges large
and small, are sprayed by different sizes of the Airostyle sprayer.
Stoving takes place in most cases, and the work of spraying effects a
great saving, one man being able to do the work of at least three under
the old brush system.
Some very beautiful effects are obtained in stoves intended for use
in drawing, dining and reception rooms, by spraying various coloured
semi-transparent lacquers over silver-bright iron or steel. Rich reds,
browns, greens and blues in various shades are produced, and the bright
surface beneath the lacquer gives a very pleasing and artistic effect.
Stoving produces the necessary hardness of the lacquer, which may be
regarded as being very durable.
SPECIAL MACHINES.
The Berkel and Parnall's Slicing Machine Co., Ltd., whose extensive
works are at 6, Bow Common Lane, London, E., have had a plant for
paint spraying in use for the last four years, and find it to be quite
successful and a great saving of time over the old method of applying
the paint by means of brushes, in addition to a superior finish being
obtained. The sprayer in this case is the "Invincible," and the paint
is sprayed on under pressure varying according to the nature of the
work. The iron parts which go to make up the slicing machine are first
primed and stoved and any imperfections stopped in the usual manner.
They are then painted by means of compressed air and again stoved,
after which they receive a further coat, which is also stoved. Various
ornamentation in gold is then put on, mostly by the transfer process,
although certain parts require lining by hand. The final coat of
varnish is given by means of brushes, it being found that this is
the most economical way for this particular class of work. In this
particular it will be observed that the method differs from that used
in many other works where all the operations are done by spraying,
including a final coat of varnish. The colour used for the paint is a
bright red. There are two spraying cabinets with the usual exhaust, and
turn-tables are employed for turning the parts round to receive the
coat of paint. It may surprise some readers to learn the very large
extent to which these slicing machines are used throughout the world
for various purposes.
GITTINGS, HILLS AND BOOTHBY, LIMITED.
The plant for spraying in use in these works is principally intended
for experimental purposes in connection with the preparation of
paints, varnishes and lacquers of various descriptions which the firm
manufacture. An up-to-date type of pistol is used, with a pressure
not exceeding 30 lbs. to the inch. The work is done in a small closet
with glass sides open at one side, and a small turn-table is employed
upon which to place the article that is being sprayed. Some admirable
results are obtained with the aid of gold lacquers. It is found that
in certain varnishes the application of heat is an advantage, but as
a rule the spraying is done cold. Among the articles which have been
painted are motor cars and various smaller appliances.
THE KINGSBURY MANUFACTURING CO., LTD.
A typical plant for finishing picture frames, furniture, fancy
articles such as wood, cane and other ornamental baskets, is that of
the Kingsbury Manufacturing Co., Ltd., 1, Markfield Rd., Broad Lane,
Tottenham, N. This firm are the inventors of what is known as the
"Inolite" system of gilding, which is described as an ideal process.
Certainly the work produced is as near perfection as one would desire,
the gilding being excellent in appearance, while it is guaranteed for
five years to be free from discoloration or tarnishing. The process
consists in applying by means of spraying, first, a coat of special
enamel, which when dry is rubbed down with a solvent applied by a
pad. Upon this is sprayed a coat of gold paint, and a final coat of
colourless celluloid varnish is given which protects the gold from
tarnishing. The process adopted is described in greater detail under
the head of "Picture Frame Finishing" in this book.
[Illustration: Fig. 103.--VIEW FROM ONE END OF MESSRS. LUCAS, LTD.,
AIROSTYLE PLANTS, SHOWING FAN AND COMPRESSOR DRIVES.]
The coloured celluloid enamels which are applied to fancy baskets,
etc., have a very attractive metallic appearance, which is far superior
to the ordinary crude bronzy effect. Another speciality of the firm is
the finish of frames in special black, which gives a perfectly smooth
finish which might be called "egg-shell gloss." It is quite artistic in
appearance, eminently suitable for the particular purpose, and gives a
durable frame at a comparatively small cost.
The firm estimate the saving of time by using the spraying as compared
with that of employing a brush is as 5 is to 1. They point out that
a little extra material is required, but this is not begrudged as it
possesses advantages in an increased durability of the protective
coating.
THE GAS LIGHT AND COKE CO.
Several of the works of this company, which deal with gas meters,
are fitted with paint spraying installations. The branch at Laburnum
Street, Kingsland Road, in charge of Mr. W. F. Fagan, may be taken as
a type. Two Aerographs and three Airostyles are in use. The old meters
that come to the works are examined, and if the paint is in fairly good
condition the surface is rubbed down with pumice stone and water, but
if it is much decayed the meters are placed in a hot bath containing a
solution of lime and caustic soda, and allowed to remain in it a short
time, when the paint becomes so soft as to be easily removable. The
surface of new tinplate is cleaned down with spirit, when it is quite
ready to receive the coat of paint. At these works many different makes
of meters come in to be dealt with, hence various masks are necessary
to protect those parts which it is not desired to spray. The pressure
used here is rather more than usual, being 40 lbs. to the sq. inch. The
time taken to paint a meter is very small, as can be understood when
it is said that two men working on five-light meters can turn out 30
an hour. Before the spraying apparatus was put in, about a year ago, a
man could paint with a brush about three meters in an hour, so that,
with the present system, there is an immense saving. It is calculated
that the whole of the original outlay of putting in the plant will be
returned at the end of about a year.
The masks or shields having been placed in position, a cap is placed
over each union and the paint is sprayed on. The meters are turned out
at the rate of 900 to 1,500 a week of 48 hours. The spraying apparatus
is provided with the usual exhaust consisting of two 9-inch holes
to each cabinet, with grating over. About 10 per cent, more paint is
allowed than that used when it is applied by hand, but the greater part
of this goes on the surface, and the coat of paint as a protector is
distinctly improved. The exhaust is carried up to the roof, but the
actual loss of paint is very small.
Fig. 108 shows a general view, and a large central draught steel
plate fan is employed to exhaust the hoods, and to drive this and the
compressor a gas engine is employed. The compressor is of the type
illustrated in Fig. 71, page 115, and can just be discerned behind the
gas engine.
Fig. 109 shows a gas meter in position, with the necessary masks fixed,
and Fig. 110 shows the operator about to spray-paint same. This plant
has been in daily operation for more than two years.
THE GAS METER CO., LIMITED.
The installation of a spraying plant at the works of this firm, which
are at 238, Kingsland Road, have been in operation for rather less than
a year, but has proved quite satisfactory. Various types of gas meters
are sprayed with one coat of Torbay paint, which is an iron oxide paint
of high quality, and the one coat possesses amply sufficient quality
to give a good covering. Prior to painting the surface of the tinned
plate which is used for gas meters, it is cleaned down with a piece of
waste dipped in spirit. Masks are used to fit over name plates, etc.,
and the spraying is done in the usual cabinet, with an exhaust. A three
or four-light meter takes about two minutes to do, and the larger
sizes, of course, longer in proportion. All sizes up to and including
500-light meters are sprayed, but those larger, up to 1,000 lights,
are a little too big to handle. The greater part of the meters are
done in deep red oxide iron colour, but three other colours are used
in addition, as may be required. The meter to be sprayed is placed on
a turn-table which bears on a sharp steel point and has on its upper
portion spikes or ridges, to hold the meter in position. The Aerograph
spray is employed in this case.
[Illustration: Fig. 104.--GENERAL VIEW OF AIROSTYLE PLANTS AT MESSRS.
LUCAS' LTD.]
[Illustration: Fig. 105.--J. LUCAS, LTD., AIROSTYLE PLANTS, SHOWING THE
AMPLE SPACE BETWEEN HOODS.]
[Illustration: Fig. 106.--J. LUCAS, LTD., AIROSTYLE PLANTS, SHOWING
THE METHOD OF EMPLOYING RACKS TO GREATER ADVANTAGE, AND ALSO GIVING A
CLEARER IDEA OF THE LARGE FAN EMPLOYED.]
CHAPTER X.
PAINTS, LACQUERS, VARNISHES, ETC. USED IN SPRAYING.
Under the head of "Paints used for Dipping" some information has been
given in respect to the paints suitable for that purpose. Some, but not
all, paints are suitable for both dipping and spraying, the exceptions
being the heavier or more viscous compounds, which are not suitable
for painting by immersion because they are too thick. Tar, enamel, and
the heavier varnishes may be given as examples, although they may be
successfully applied by the spraying process.
Sometimes in dealing with the heavier compounds the application of
heat is an advantage. This may be applied to either the paint or
the compressed air or to both in order to increase the fluidity of
the compound. It is important when heat is thus applied that the
temperature of the room in which the spraying is done should be
raised correspondingly, so that the heavier paints, enamel, etc.,
do not congeal by being directed against a cold surface. Under most
circumstances it is unnecessary to apply heat, provided that the
spraying room is kept at a temperature of not less than 60° F. both in
summer and winter.
As already intimated, the preparation of paints, lacquers and varnishes
for both dipping and spraying necessitates a close study of the special
requirements. In the case of paint the particles of pigment must be
very finely divided as coarse material would tend to choke up the
spraying apparatus, or if even they did not actually have that result
they would require a greater pressure of air and thus add to the cost
of working. Zinc oxide, the various grades of black and most bright
reds, are examples of finely ground pigments which are well suited for
spraying.
In buying materials for this purpose it is well to purchase of those
firms who have made a special study of the subject. The following is a
list of a few such firms, all well known to the writer, and although it
by no means exhausts the list yet anyone desiring to buy materials may
very safely leave themselves in their hands.
Messrs. Docker, Bros., Ltd., Birmingham; Gittings, Hills and Boothby,
Ltd., Tower Varnish Works, Long Acre, Birmingham; Goodlass, Wall and
Co., Ltd., Seal Street, Liverpool; A. Holden and Sons, Ltd., Bradford
Street, Birmingham; Indestructible Paint Co., Ltd., King's House, King
Street, London, E.C.; Lewis Berger and Sons, Ltd., Homerton, London,
N.; Llewellyn Rylands, Ltd., Balsall Heath Works, Birmingham; Mander
Bros., Wolverhampton; Postans and Morley Brothers, Ltd, 19, Lionel
Street, Birmingham; The Frederick Crane Chemical Co., Birmingham;
Thornley and Knight, Birmingham; Wilkinson, Heywood and Clark, Ltd.,
Caledonian Works, Poplar. E.; Pinchin, Johnson and Co., Ltd., Bevis
Marks, London.
The following are American firms:--
The Moller and Schumann Co., Chicago, Ill.; John Lucas and Co., Inc,
Gibbsboro', N.J.; The Chicago White Lead and Oil Co., Chicago, Ill.;
John W. Masury and Son, New York, N.Y.; The Glidden Varnish Company,
Cleveland, O.; The Sherwin-Williams Co., Cleveland, O.;
STOVING ENAMELS.
We now reach these important enamels, and extract the following from
the foreword of the little book above mentioned. Messrs. Wilkinson,
Heywood and Clark claim to be the first successful makers of stoving
blacks, which was in the days before the introduction of bicycles.
Though originally introduced for cycle work, stoving enamel produces a
most successful finish for all kinds of materials. In the United States
of America such enamels are used in great quantities for finishing
standardised motor bodies. These black enamels have gained a very high
name for themselves, as properly baked they are extraordinarily hard,
brilliant and tough, and when applied over such material as tin sheets
are flexible enough to withstand being bent double without showing
signs of cracking. An important feature are the coloured enamels made
by the same firm, which run through a whole series of yellows, reds,
browns, greens and blues, and are hard, durable and tough, and can be
stoved without changing colour. We extract the following notes on the
"Application of Stoving Enamels," and fully endorse the recommendations
offered:--
1. All work should be perfectly free from dirt, grease or oil, before
application of enamel.
2. Every trace of moisture should be removed before enamelling. This
can be effected by stoving the work, previous to enamelling, at a light
heat. Moisture on work will cause enamel to blister and burn.
3. Always when using brushing or dipping enamels, allow the enamel
to set slightly (i.e., after the surplus paint has dried off) before
putting in the baking oven. This will prevent uneven stoving and
eliminate "fat edges," as far as possible.
4. Oven heat should be increased gradually. Never place enamelled work
into a hot oven at once, but raise the heat by degrees, until the full
temperature is obtained.
5. Most of our enamels are sent out slightly thick; should an easier
working material be desired, in the case of colours or blacks, add
kerosene gradually until the required consistency is obtained.
Coloured enamel should always be stirred before use, to prevent the
pigment settling and the light medium rising. If this is not done, the
appearance of the work will lack body and appear dull and lifeless.
This applies especially to dipping enamels. To render white stoving
enamel thinner, add pure turpentine only, stirring well, until a
uniform consistency is obtained.
6. It is quite possible to over-bake enamels and spoil the colours,
and likewise under-baked enamels will not be tough enough to withstand
hard wear. Particular attention should be paid to the directions on the
package labels, as the various pigments require different temperatures.
7. Stoving enamels, if left in an opened can, tend to thicken
considerably. For this reason, keep the can closed when not actually
using the enamel.
For thinning purposes we recommend kerosene. Sp. gr. 810 at 60° F.
8. Ovens should be properly ventilated to allow the proper oxidation
necessary in baking.
ENAMELS.
It has already been pointed out in these pages that the success of
painting by dipping, spraying, "flowing on," in fact, all other
mechanical means, depends upon the exact properties of the materials
used. The same is true with enamels, which are made from a large
variety of formulæ so as to dry slowly or quickly in the air, or when
subjected to heat in a stove. The author feels he cannot do better than
take as a guide to the properties of enamels in general the extremely
useful handbook published by Wilkinson, Heywood and Clark, under the
head of "Enamels for every Purpose." This book gives practically
all the information concerning enamels likely to be required by the
average user. The products are divided up under different heads, for
example, one page is headed "Heat Resisting and Slow Drying Enamels."
These dry fit to handle in 16 hours, and dry bone hard in 24 hours.
They are made to withstand heat up to 212° F., and for this reason are
suitable for enamelling iron baths, radiators, etc., particularly so
as to effectively resist hot water without softening or peeling. They
are made in a number of beautiful colours. A somewhat similar series
of enamels is made which dry quicker, viz., in 8 hours fit to handle
and quite hard in 12 hours. They are useful for touching up radiators,
stoves, steam pipes, etc., and are made in white and a dozen or more
colours. The next series which demands our attention are "Dipping Air
Drying Enamels." They dry in 8 hours and are quite hard in 12 hours.
They are claimed to produce a finish equal to that obtained by a quick
air drying brushing enamel with the labour of brushing eliminated. For
a finish done by immersing the article to be painted these are capital
enamels, but they require to be used with a stirrer of some sort in the
tank.
HINTS ON STOVING OR BAKING.
The degree of heat to which an article is subjected after being painted
or japanned will obviously depend upon the kind of coating used. It
is safe to assert as a general rule that the heat applied must not be
higher than the particular paint or enamel is made to withstand, for,
if this be exceeded, it will inevitably result in a loss of elasticity,
of the protecting film and, hence, its durability.
The following hints are taken from a very useful little pamphlet
issued by the Moller & Schumann Co., of Chicago, Ill. The degrees of
temperature given refer to their products, and would doubtless have to
be modified in some cases, according to the nature of the paint being
dealt with. They will, however, form a very useful guide.
[Illustration: Fig. 107.--J. LUCAS, LTD., AIROSTYLE PLANTS, SHOWING THE
TWO BAYS OF ONE COMPLETE UNIT.]
[Illustration: Fig. 108.--AIROSTYLE PLANT INSTALLED FOR MESSRS. THE GAS
LIGHT AND COKE CO., LTD. GENERAL VIEW.]
BLACK JAPAN FINISHES.
One or more coats rubbing finish japan, reduced as thin as possible and
still cover well.
Bake each coat at 250° to 350° for 3 to 4 hours. Sandpaper each coat
lightly.
One or more coats finishing black japan reduced to brushing consistency
(not too thin).
Bake each coat at 300° to 350° for 3 to 4 hours. Sandpaper each coat
lightly. Rub the last coat with pumice. Apply transfer and striping to
last coat of japan.
Bake these at 150° for 1 to 2 hours.
One or more coats finishing copal brushed as it comes from the can.
This protects the transfer and striping and increases the depth of the
finish.
Bake each coat at 175° for 2 to 3 hours. Rub each coat and polish the
last coat.
If finishing copal is omitted, leave the last coat of japan in gloss,
or rub and polish as preferred.
STEEL FURNITURE ENAMELS.
One or more coats of first coat enamel, reduced as thin as possible and
still cover well. When brushed on, use steel preservative for back and
underside of metal, one coat only, baked at same time as first coat of
first coat enamel.
Bake each coat at 250° for 3 hours. Sandpaper each coat lightly. One or
more coats of finishing enamel.
Bake each coat at 250° for 3 hours. Sandpaper all but the last coat.
Rub the last coat with pumice.
Enamels when rubbed have a different colour than the surface colour;
this must be taken into account in finishing.
Transfer and striping, if any, should be put over last coat of
finishing enamel. Bake at 150° for 1 to 2 hours. One or more coats of
finishing copal.
Bake each coat at 175° for 2 to 3 hours. Rub each coat, and polish the
last coat.
If finishing copal is omitted, leave the last coat of enamel in gloss,
or rub and polish as preferred.
The same enamel will bake to different shades at different heats and
varied lengths of time, so care must be observed to get uniform results.
IMITATION WOOD EFFECTS.
One or more coats of ground colour; back of metal one coat steel
preservative, both reduced as thin as possible, and still cover well.
If the steel preservative is used by dipping, only one coat of ground
colour is generally used.
Bake each coat at 250° for 3 hours. Sandpaper each coat of ground
colour. One coat of graining colour, reduced with turpentine brushed
on, and grained by hand, or with tools as in general graining. This may
be done by machine or as transfer work.
Bake the graining colour at 200° for 2 to 3 hours. Sandpaper lightly.
Put on transfer and striping, if any, over last coat of finishing
enamel.
Bake at 150° for 1 to 2 hours. One or more coats of finishing copal.
Bake each coat at 175° for 2 to 3 hours. Rub each coat. Rub and polish
the last coat.
In this work, at least one coat of finishing copal is necessary to
protect the graining colour.
WHITE WORK--BEDSTEADS, ETC.
White work cannot be finished with one coat, because no white pigment
has sufficient covering power.
Two or more coats of first coat white enamel.
Bake each coat at 120° to 150° for 3 to 4 hours. Sandpaper each coat
lightly.
Two or more coats of finishing white enamel.
Bake each coat at 120° to 150° for 3 to 4 hours. Sandpaper each coat
lightly except the last coat.
For gloss finish, leave last coat as it is; for eggshell finish, rub
the last coat.
Finishing copal is rarely used over whites because of colour.
TRANSPARENT COLOUR VARNISHES.
These varnishes are used over smooth, clean, bright metal. As the metal
shows through the varnish, no primer or filler can be used.
One coat only is applied, usually by brushing or by a coating machine;
however, it may be dipped or sprayed.
Bake at 225° for 3 hours.
The more these varnishes are reduced, the lighter the colour becomes.
[Illustration: Fig. 109.--AIROSTYLE PLANT INSTALLED FOR THE GAS LIGHT
AND COKE CO., LTD., SHOWING HOOD IN GREATER DETAIL AND A METER WITH
MASKS AFFIXED.]
SAFE BAKING HEATS OF PIGMENT COLOURS.
All colours are more or less affected by heat. They lose their
brilliancy, become very much darker and sometimes turn black when baked
at too high a heat.
Prolonged heat (not too high) kills the elasticity of the enamel. It
does not affect the colour.
To assure brilliancy of the colour, the following highest heats can be
used with safety.
White 160° 4 hours.
Pale Blue 175° 2-3 "
Pale Gray " " "
Pale Green " " "
Pale Yellow " " "
Gray 200°-225° 4-3 hours
Bright Red " " " "
Green " " " "
Yellow " " " "
Dark Blue " " " "
Olive Green 240°-275° 4-3 hours
Maroon " " " "
Brown " " " "
Black - any heat up to 600°
COMMENTS ON THE ABOVE.
A well-known English firm, commenting on the above says:--
"Generally speaking, the information given therein is quite correct,
though it should be remembered that instruction as to stoving
temperatures which might be quite correct with one maker's materials,
might be quite wrong with another's.
"We notice they recommend that all black japan finishes should be
stoved at from 250 to 350 degrees. This is the general practice in
England, but it also happens that some firms cannot use these high
temperatures or some goods will not stand it, and black japans have to
be supplied which can be stoved at temperatures of about 180 or 200
degrees Fahr. Such qualities cost rather more to produce.
We also notice it is recommended that finishing varnish should be
stoved at 175 degrees Fahr. Personally, we cannot make any clear
finishing varnishes which will stand this temperature without
discoloration, and even if used over black japan, they would discolour
the lining or the striping thereon.
"The temperatures recommended for coloured enamels are also higher
than we find satisfactory, and the statement made that the same enamel
will bake to different shades at different heats, and that therefore a
uniform temperature is necessary to obtain uniform results, seems to
confirm our view. In practice we think that uniform results can only
be obtained by using a lower temperature. If a workman has to watch
the thermometer in a stove to make sure that his enamels will always
discolour to the same degree, you can rely upon it that in practice
accidents would soon happen."
DIPPING AND SPRAYING PAINTS COMPARED.
From the above it can readily be seen that it is necessary to exercise
considerable care in the selection of paints for both of these
processes. The following opinions on this important subject are given
by the firms named.
Messrs. John Lucas and Co., Inc., Gibbsboro', N.J., U.S.A., say:--
"It is our experience that a paint which is suitable for dipping
purposes can also be manipulated for spraying. A paint to be suitable
for spraying depends largely on two factors, namely:--Gravity, or
weight per gallon, and consistency, or fluidity. A paint made from
pigments which are heavy gravity will not produce good results for
spraying, just as it will not prove satisfactory for dipping, because
of the tendency for the pigment to settle out. In the case of spraying
such paints produce an uneven finish. A paint such as is ordinarily
used for dipping contains sufficient light gravity pigments to make
possible reduction with the proper vehicles (depending on the desired
finish) so that by spraying a satisfactory coating can be produced
so far as finish is concerned. We are not certain whether a coating
produced by spraying will wear as long as a coating which is applied
either by dipping or by brushing."
* * * * *
The Chicago White Lead and Oil Co., Chicago, Ill., say:--"There is no
very intricate or specific formula for this class of material. The
following rule we think will prove a safe one to follow:--
"Always select a pigment which will stay in suspension, and also hold
with it the extenders such as very fine silica. The addition of a very
fine silica to all dipping or spraying paints will add materially
to the flowing off and levelling of the finish. The pigments should
be ground very fine in varnish, the grade of varnish depending upon
the quality of the material to be produced, and reduced to working
consistency with varnish and turpentine, or naphtha.
"Linseed oil should be avoided in the preparation of dipping paints,
as the tendency of linseed oil to wrinkle is very objectionable.
Chemically pure colours, such as green, yellow, para toners, etc., are
best adapted as colour bases.
"The above constitute the principles upon which we have produced
extremely satisfactory paints for the purpose named. These, coupled
with expert workmen, will produce excellent results. The average
formula for paints can only be considered as a general guide; the
successful blending, tinting, etc., must be perfected by careful and
sometimes extended experiments.
"The difference between a dipping paint and spray paint is in the
consistency. A spray paint must naturally be made thinner, and
consequently only the most dense of colours should be used and a
smaller amount of inert pigment as an extender, or leveller. A few
experiments with a spraying apparatus (of which some inexpensive hand
sprayers can be obtained) will quickly guide the paint man as to proper
consistencies to produce best results."
* * * * *
Messrs. John W. Masury and Son, of New York:--"It is practically
impossible to give full particulars regarding varnishes and enamels
for spraying and dipping, for the reason there are so many different
kinds and they vary so much owing to the different character of work
that a description of them is out of the question. In a general way
it may be said that dipping coatings must be quick setting, so as to
avoid runs and sags; it must flow out to a smooth, even surface. The
drying quality must depend upon the kind of work being done, character
of surface, subsequent exposure, and whether the coating is to be baked
or air dried. Dipping varnish and enamels are made for many classes of
work, such as all kinds of small iron castings and sheet metal work, as
well as wood work, vehicle wheels, parts of automobiles, and in some
cases wagon bodies and automobile bodies, these last only in one or two
shops. These goods include cheap black baking japans, coloured enamels
of various kinds and clear varnishes.
"In regard to spraying enamels, the 'spray brush' is gradually coming
into use. These goods must be made to suit the character of the work;
the body or viscosity of the material, the pressure used in the spray
and character of the surface to be coated, must all be taken into
consideration and properly graduated to insure suitable finish.
"In both dipping and spraying work one, two and three coats are
frequently used, sometimes the under coats are only dipped or sprayed,
while the finishing coat is applied with brush.
"The equipment for dipping will vary also with the article to be
dipped; it includes dipping tanks of suitable size and shape, racks
for hanging articles dipped, with troughs or trays to collect surplus
material. In dipping it is necessary to wipe off with brush the surplus
which gathers on lower edge of the article.
"Equipment for spraying requires besides the spraying machine a
pressure tank with suitable cocks to regulate pressure, which will vary
from thirty to fifty pounds, a suitable hood provided with fan to draw
off any fine spray away from the workman, proper racks for taking care
of the finished work. Work done with spray does not require any wiping
up."
[Illustration: Fig. 110.--AIROSTYLE PLANT INSTALLED FOR THE GAS LIGHT
AND COKE CO., LTD. OPERATOR AT WORK ON GAS METERS.]
CHAPTER XI.
SPRAYING VERSUS BRUSHING.
It will be convenient now to consider the length of time involved in
spraying, as compared with that involved when painters' brushes are
used.
In dealing with this question, it should be pointed out that while some
little gain is apparent in the actual time occupied in handling the
article, which is mostly done on turn-tables when spraying, yet no note
is taken here of the difference in handling, but only the time occupied
in covering the article with paint, japan, etc.
We will take, by way of example, a modern gas fire. Very few of these
are now brushed. It is the consensus of opinion that a gas fire takes
10 minutes to brush.
To spray one, with a superior finish, takes 30 to 45 seconds, and even
where some difficulty is experienced in handling, or where it is the
practice to have the firebricks in place beforehand, so necessitating
the use of a mask, in no case is a greater time than 1½ to 2 minutes
taken. A cycle lamp, small size, takes fully 2 minutes to brush
properly. To spray the same lamp takes 10 seconds. A gas meter, 5 or 10
light size, takes 7 minutes to brush. To spray one takes 1½ minutes,
allowing for the time occupied in fixing and removing the somewhat
elaborate mask employed for covering the indicator glass, badges,
name-plate, etc.
A motor headlight takes nearly 20 minutes to brush properly, whereas to
spray one takes but 1½ minutes at the outside.
To brush a cycle frame takes 10 minutes or so (brushing is still done
for coloured work).
To spray either in japan or colours takes 1 to 1½ minutes, and when it
is considered that a heavier coat can be applied than is the case when
brushing or dipping, it will be admitted that such a result compares
favourably even with dipping.
A 2-seater motor body takes from 25 to 45 minutes to brush properly.
To spray the same body takes only 6 to 8 minutes, and when it is noted
that a fraction of the rubbing down is necessary in the case of the
sprayed result, as against the brushed body, it will be granted that an
enormous gain is to be effected.
Where two or more colours are employed, it is difficult to make
comparisons as readily, but, generally speaking, it is the practice to
employ two instruments per operator where the colours are applied one
immediately after the other, as is the case with many electrical parts,
and in this case a gain of 4 or 6 to 1 is shown over brushed work.
In some cases it has been found an advantage to spray one coat and
to brush the other, especially where some difficulty is experienced
in masking, and, in such cases, the only way to arrive at the most
satisfactory method is by actual test.
In other cases, such as bronzing, with a celluloid medium, it is
absolutely impracticable to apply these bronzes, save with the spray,
unless the old method of varnishing and afterwards dusting on the
bronze is adopted; but, of course, against spraying, such an obsolete
method as the latter has absolutely no chance when speed is considered.
Iron piano frame manufacturers have almost universally adopted the
system of spraying bronze on the frames. Where the old-fashioned method
is still in use, it is usually because the quantity of frames to be
dealt with is hardly large enough to justify the outlay required in the
purchase of a plant.
Another advantage should be mentioned. The special celluloid japans now
largely used for application by means of compressed air obviate the
necessity of a considerable amount of rubbing down and papering, etc.,
which cannot be dispensed with when the liquid is applied by means of a
brush.
For the purpose of comparison, it may be said that these japans may
be sprayed upon such articles as buttons, medallions, electrical and
bedstead fittings, and also on wood brush-handles and furniture, large
and small, with a gain of 5 to 1 over brushing.
OBJECTIONS SOMETIMES URGED AGAINST SPRAYING.
Having explained the advantages of the spraying system, we may now
consider the objections which are occasionally raised against it.
One of the arguments most frequently used is that the effect thereby
obtained must be less durable than is the case of the brushed effect.
Why such a theory should be advanced is a little obscure, for,
theoretically, it is possible to apply, with a properly fitted plant,
a far more even coat than is the case when brushing, and seeing that
such paint is applied with the idea of protecting the article against
rust, or corrosion, or of improving the appearance, the argument is for
rather than against spraying.
However, to come to the practical side, the evidence is all in favour
of spraying, for it has been proved by many exhaustive tests by
independent persons, that, with the same material treated in the same
manner, _i.e_., either air dried or stoved after spraying or brushing,
there is no difference in the durability of the japan or paint, and
that the sprayed result has this advantage, that some little gain in
time is effected in the period occupied in drying or stoving of the
paint.
Another objection is sometimes raised to the application of paint by
means of the spray to rough and uneven surfaces. The argument here is
that it is impossible to make the paint adhere to the surface, save
with a good stiff brush.
Such arguments ignore the pressure at which the paint is applied, which
is usually between 30 and 45 lbs. per square inch, and are mainly based
on unfortunate experiences with early types of whitewashing machines,
which have already been pointed out to be entirely unsuited to painting
problems.
Again here, it may be positively stated that in no case has it been
found that a less durable finish is obtained with the spray. As a fact,
an advantage is to be recorded in that on rough surfaces the gain in
time is enormous, for such surfaces may be spray-painted as rapidly as
the smoothest surface obtainable, whereas the labour of brushing such
rough surfaces is very considerable.
Still another objection which may be mentioned is the slightly mottled
appearance which the sprayed surface sometimes shows when finished--if
such can be objected to seriously.
This objection may be met by the statement that such a mottled effect
is only apparent when the paint has not been specially prepared for
spraying, and is mainly due to the fact that mediums used dry rather
too rapidly and do not allow the paint (which is, of course, applied
in minute spots) to flow out.
The remedy is naturally to re-model the paint should the mottled
appearance be objected to, but most certainly such an effect, if
not pronounced, is not any worse than brush marks, which are always
noticeable unless rubbing down has been done.
In passing, it may be stated that most of the large paint and varnish
manufacturers have experimental plants for producing spraying
materials, and they are naturally well able to answer any queries which
may be likely to arise and which may not be adequately dealt with here.
Many firms who consider the question of adopting a spraying plant seem
to have the idea that while the principle is admirable for many trades,
yet it cannot be successfully employed in their particular case, and
one frequently finds the manufacturer of small goods wondering why his
neighbour opposite, who makes, we will say, motor bodies, does not
install a plant, although, of course, in his own case the question is
impossible. Most probably, at the same time the said neighbour has
precisely similar thoughts, save that he considers the only proper use
for a plant is in small work.
Occasionally one hears the opinion advanced that primers or fillers
cannot be applied with a sprayer, or, if so applied, it is at a risk
that they will either crack or peel off afterwards.
This objection may just as readily be advanced in the case of brushing.
If trouble of this kind occurs, it is not due to the method of
spraying, or brushing, so much as to the way in which the paint has
been used. This statement sounds paradoxical, yet it will be understood
by practical men. For instance, it is obvious that motor bodies, par
exemple, must be dealt with by the expert coach-painter as far as the
methods, number of coats, etc., to be employed are concerned, even
though the work may be carried out by unskilled labour, and naturally
whether brushed or sprayed, motor bodies cannot be well done by novices.
To summarise, it may be confidently stated that whatever difficulties
there may be in the application of paints, enamels, varnishes,
lacquers, etc., by means of brushes in the ordinary way, these are
certainly never accentuated but are in most cases considerably lessened
by the use of an adequate spraying plant.
SPRAYING AND DIPPING COMPARED.
In considering those articles which may be dealt with either by dipping
or spraying, the manufacturer has first to take into account the number
of coats necessary.
If, for instance, to produce the correct finish on a cycle frame, when
dipping, needs three coats, and assuming that the same effect may be
obtained in two when spraying (and this is frequently the case), then
spraying must be considered to rank favourably with dipping, and if
allowance be made for the time taken to drain, and the room occupied
with an elaborate dipping plant, then again spraying scores, for a
cycle frame can be sprayed in 1 to 1½ minutes, or, say, 40 to 50 frames
per hour, which is very little, if any, less than can be comfortably
dealt with by dipping, and, of course, no time is lost in draining.
If, on the other hand, gas is so cheap as to be of little consequence
whether two or three stovings are necessary, and if some of the work
can be done with two coats, then the saving effected when spraying
would not be sufficient to warrant the outlay necessary for a modern
compressed air plant, _unless_ a fair proportion of coloured work, not
easily dipped, was required to be dealt with. In this latter case, a
spraying plant ought to receive very serious consideration.
To take another case. Some gas fires may be dipped, but, owing to their
weight and to the fact that they are seldom entirely free from grit or
dust, they are not a satisfactory type for dipping, and we venture to
state that all the leading gas engineers have dropped the question of
dipping such work in favour of spraying, although in some cases, for
gas cookers, the accessories, such as burners, bars, racks etc., are
dipped.
Such accessories are as readily sprayed, but as only one coat is
applied, naturally no saving is shown over dipping.
Other goods sprayed or dipped are steel implements, hoes, spades,
shovels, axes, picks, etc., and in some cases it is an advantage to
dip where the same colour, black, red, etc., is needed, say, half-way
up the spade or hoe, but otherwise spraying should be adopted; and, of
course, in many cases where two colours are employed it is out of the
question to dip, the only alternative being to spray or brush--spray
for preference on account of the enormous saving of time over brushing.
Where very small articles are dealt with in bulk and can be so handled
that trays may be used, then these are undoubtedly better dipped; but
if various colours are needed it is better to still use the trays, but
to spray them, as the speed is approximately the same as when dipping.
A tray full of camera parts is sprayed almost instantaneously and with
a far better finish than if dipped.
To sum up the various arguments advanced on this subject, we may come
to the following conclusion.
As already intimated, the saving effected by painting by immersion or
by spraying as compared with brushing is very large indeed, provided
that a properly equipped plant is employed, and the paint or enamel is
exactly fitted for the purpose. The question must often arise as to
whether dipping or spraying is the best and cheapest to employ. The
answer is that everything will depend upon the nature of the article
that is to be painted. Speaking generally, painting by immersion
possesses many advantages, because the actual work of applying the
paint is done in a few minutes and every part of the article is covered
with paint at one time. In reaping machinery, iron treads of staircases
and many other parts of the kind in which there are a large number of
small parts or depressions, paint dipping cannot be improved upon; on
the other hand, spraying possesses distinct advantages in dealing with
many classes of goods which are of such a shape or character that if
the paint were applied by dipping some accumulation in parts would
inevitably occur.
A decision on the subject can only be arrived at after a very careful
study in comparison of the two methods. It will frequently be found
that, on the whole, the most economical plan to pursue is to dip the
first and subsequent coats, excepting the last, and to spray this on,
particularly when it consists of varnish or a viscous liquid. It is
in this particular that one can draw a wide distinction between the
two methods. In dipping, the paint must not be very thick, and, as
previously stated, in designing a paint for the purpose the greatest
effort is made to produce one which gives a happy medium between
excessive thickness and the reverse, too thin a coat. Just as soon as
the peculiarities of the article to be painted necessitate the use of
all thick paint or enamel it must be considered that dipping is not
suitable, but that spraying is. The latter may be employed successfully
with any liquid up to the thickness of tar.
[Illustration: Fig. 111.--AIROSTYLE PLANT SHOWING VENTILATOR AND
PORTION OF HOODS FOR 4 OR 6 HOODS PROVIDING FOR SUBSEQUENT ENLARGEMENT.]
[Illustration: Fig. 112.--ELEVATION OF SPRAYING PLANT.]
[Illustration: Fig. 113.--ELEVATION OF SPRAYING PLANT.]
[Illustration: Fig. 114.--PLAN OF FIGS. 111 AND 112.]
CHAPTER XII.
THE ARTISTIC APPLICATION OF PAINT SPRAYING.
Some of the smaller and more delicate types of spraying apparatus are
largely employed for such purposes as the following:--Black and white
and water-colour drawing, photograph finishing, preparing pictures
for process blocks, Christmas cards, window tickets, embossed cards
and small stencil and shaded work on fabrics, wood, glass, metal,
leather, etc., lithographic work, picture painting in oils, decoration
of pottery and stencil and shaded work of all kinds. They are also
employed for producing very charming effects in wallpaper. The writer
has seen most creditable examples of work done in this way on menu
cards, lamp shades, and even stencilled ornaments on men's ties.
A few examples of this class of work are given in the accompanying
illustrations.
It may be pointed out that when decorative work is required on metal
work or engineering appliances, it can in most cases be done by
spraying without much difficulty, aided in some cases by stencils
specially cut for the purpose. Thus the outline of a trade mark, a
monogram or a coat-of-arms, or heraldic device can be easily sprayed
and be then finished by hand.
Again, the lining on a motor or carriage can, if care is taken, be done
by the same means, although it must be said that the result is never
quite equal to that produced by the hand of a skillful worker.
In relief work, such as ornamental iron, pressed paper, etc., some
pretty effects may be produced by spraying a different colour to
that of the ground in such a manner that only one side of the relief
receives the second colour. This is effected by directing the spray
from the side. Most readers will be familiar with these effects
produced on menu cards, concert programmes, etc. The possibilities in
connection with relief metal work are many.
Another series of effects in which brilliancy of colouring is required
may be referred to in passing. Sometimes a bright red or a bright green
is desired for the finish of a particular piece of work. In such cases
a use of the process known as "colour glazing" is recommended. For
example, an agricultural implement or any other article which it is
desired should have a bright crimson finish can be first painted with
Venetian or Indian red, by either spraying or dipping, and then have
a coat of crimson lake, which will give an excellent effect. As the
crimson lake is somewhat fugitive a protecting coat of varnish will be
required.
All glazing colours may be applied by dipping, because, being
semi-transparent, they are all very fine, and the coats may be thin,
but the varnish should be applied by spraying or by hand. It may of
course, be of a variety suitable for baking or stoving if required.
This process is an alternative to using coloured enamels, and in some
cases gives better results. Much depends upon the colour and the
constituents of the enamels. Many of the lakes are very sensitive to a
high heat, which changes the colour to a dirty brown. In such cases a
final coat of stoving varnish, if carefully handled, will be safer than
some grades of enamel.
SCUMBLING AND COLOUR GLAZING.
For convenience of reference we include a short list of glazing colours
taken from Andrew Miller's "Scumbling and Colour Glazing," published
by the Trade Papers Publishing Co., Ltd., 365, Birkbeck Bank Chambers,
London, W.C.
GLAZING.
The principal colours used for glazing are cadmium, crimson lake,
Prussian blue, lemon and orange, chrome, yellow, Brunswick green,
carmine, madder lake, Chinese blue, cobalt, indigo, gamboge, terra
verte and emerald green. These colours may be used ground in either
linseed oil, turpentine or water. Some of them are rather expensive,
but the coat being very thin a little colour goes a long way.
Following is a list of ground colours with the glazing which may be
used in conjunction with them. They by no means exhaust the range of
effects, but are given as suggestions:--
[Illustration: Fig. 115.--DESIGNS FOR LAMP SHADES (OPENED OUT) DONE BY
SPRAYING.]
REDS.
APRICOT.--Ground made up with zinc white, middle chrome, and
vermilionette, glazed with crimson lake.
BEGONIA.--White zinc, vermilionette and Prussian blue, glazed with
brown madder lake.
CARNATION.--White zinc and vermilion, glazed with crimson madder lake.
CLARET.--Zinc oxide, Venetian red and vermilion glazed with brown
madder lake; or zinc oxide and ultramarine blue, glazed with carmine.
CORAL.--White zinc, vermilion and lemon chrome, glazed with crimson
lake.
FLESH COLOUR.--White zinc, yellow ochre and Venetian red, glazed with
burnt sienna.
GERANIUM.--Bright Derby red and orange chrome, glazed with crimson lake.
LILAC.--White lead, vermilion and ultramarine blue, glazed with brown
madder lake.
MAGENTA.--Zinc oxide and ultramarine blue, glazed with crimson lake.
PEACH.--Zinc oxide, vermilion and lemon chrome, glazed with cadmium
(deep); or white lead and Venetian red glazed with carmine.
PLUM.--Zinc white, Indian red, and ultramarine blue, glazed with
carmine; or white lead and Indian red, glazed with ultramarine blue.
POMEGRANATE.--Zinc white, Venetian red and lemon chrome, glazed with
burnt sienna.
RUSSET.--Venetian red, orange chrome, lemon chrome, glazed with emerald
green (thin).
ROSE.--Zinc oxide and vermilion, glazed with crimson lake; or white
lead and lemon chrome, glazed with carmine.
TERRA-COTTA.--White zinc and Venetian red, glazed with burnt sienna.
BLUES.
AZURE BLUE.--Zinc oxide and ultramarine blue, glazed with cobalt.
BRONZE BLUE.--Zinc white and Prussian blue, glazed with black japan.
CHINA BLUE.--Zinc white, cobalt and raw sienna, glazed with indigo.
GOBELIN BLUE.--White, blue black, Prussian blue, glazed with emerald
green.
MARINE OR SEA BLUE.--Ultramarine, ivory black, glazed with cobalt; or
white, raw sienna and cobalt, glazed with indigo.
METALLIC BLUE.--Zinc white and cobalt, glazed with emerald green; or
zinc oxide, Prussian blue, black, glazed with indigo.
MAUVE.--Zinc oxide and cobalt glazed with carmine; or zinc oxide and
celestial blue glazed with carmine.
PEACOCK BLUE.--Zinc oxide and ultramarine, glazed with emerald green;
or zinc oxide and Prussian blue, glazed with cobalt.
TURQUOISE.--Zinc white and cobalt, glazed with emerald green.
WEDGWOOD.--Zinc white, Prussian blue, glazed with terra-verte.
YELLOWS.
AMBER.--Zinc white, golden ochre, glazed with cadmium (deep); or white
lead and lemon chrome, glazed with cadmium.
ANTIQUE BRASS.--Zinc white lead, orange chrome, glazed with Vandyke
brown or black japan.
BRASS.--Yellow ochre, white lead, orange chrome glazed with Vandyke
brown.
CANARY.--Zinc white and Naples yellow, glazed with emerald green (thin).
CHAMOIS.--Zinc white and middle chrome, glazed with terra-verte.
CITRON.--Zinc white and middle chrome, glazed with brown madder lake
(thin); or white lead, Venetian red, lemon chrome, glazed with Prussian
blue.
DAFFODIL.--Zinc white, lemon chrome, glazed with burnt sienna.
GOLD.--Zinc oxide, golden ochre, vermilionette, glazed with raw sienna.
OLD GOLD.--Middle chrome, vermilion, burnt sienna glazed with cobalt
(thin); or zinc oxide, Oxford ochre, glazed with burnt sienna.
PRIMROSE.--Zinc oxide, lemon chrome, Naples yellow, glazed with emerald
green.
TOPAZ.--Zinc oxide, raw sienna, lemon chrome, glazed with cadmium
(deep).
GREENS.
APPLE GREEN.--Zinc oxide, Prussian blue, glazed with cadmium (middle);
or lemon chrome, zinc oxide, celestial blue, glazed with lemon chrome.
DUCK-EGG GREEN.--Zinc oxide, lemon chrome, glazed with Prussian blue.
EAU-DE-NIL.--Zinc oxide, lemon chrome, Prussian blue, glazed with
emerald green.
GRASS GREEN.--Zinc oxide, Oxford ochre, glazed with cobalt.
IVY GREEN.--Zinc oxide, lemon chrome, burnt sienna, glazed with
Prussian blue.
MYRTLE GREEN.--Zinc oxide and ultramarine, glazed with emerald green.
OLIVE.--Zinc oxide, lemon chrome, burnt sienna, glazed with emerald
green.
BROWNS.
CHESTNUT.--Yellow ochre and middle chrome, glazed with burnt sienna; or
burnt sienna and orange chrome, glazed with Vandyke brown.
CHOCOLATE.--Burnt sienna, vermilion, ultramarine glazed with crimson
lake; or burnt sienna and Indian red, glazed with Vandyke brown.
CHERRY.--Raw sienna and burnt sienna, glazed with raw umber.
NUT BROWN.--Venetian red, lemon chrome, zinc oxide, glazed with burnt
sienna.
GRAYS.
COOL GRAY.--Zinc oxide and ivory black, glazed with Prussian blue.
DOVE.--White, ivory black, Prussian blue, glazed with terra-verte.
FAWN.--White, raw sienna, glazed with raw umber.
HELIOTROPE.--Zinc oxide, vermilionette, glazed with ultramarine.
LAVENDER.--Zinc oxide, ultramarine and carmine, glazed with cobalt.
MOUSE GRAY.--Zinc oxide, Prussian blue, glazed with burnt umber.
PEARL GRAY.--White, Prussian blue, and vermilion, glazed with terra
verte; or zinc oxide, vermilion, glazed with emerald green.
SILVER GREY.--Zinc oxide, ivory black, glazed with indigo.
OPAL.--Zinc oxide, celestial blue, glazed with burnt sienna.
WARM GRAY.--Zinc oxide, Venetian red and ivory black, glazed with
Vandyke brown.
WEDGWOOD GRAY.--Zinc oxide, Prussian blue, glazed with terra verte.
NOTE.--The terms "Zinc white," "White zinc" used above, all mean pure
zinc oxide.
SCUMBLING AND GRAINING.
It is sometimes desired to obtain a different effect from plain paint
or enamel, and to either imitate graining, such as old oak or to give
mottled effects. Both processes are produced by scumbling, which means
that the ground and finishing colours are different in hue or in
intensity, and that portions of the latter are removed to show part of
the ground. Thus, in imitating oak, the ground might be painted with a
mixture of zinc oxide and yellow ochre, and the graining colour be made
of burnt umber and raw sienna. Both coats could be applied either by
dipping or spraying, but while the latter is wet, portions should be
removed by combs and by the thumb held over a piece of rag, both marks
being intended to represent the grain of the wood. In other cases,
the colours may be applied as before, and the last coat, while wet,
be wiped away at the edges, or in the case of relief metal work, at
the highest parts. Again, some excellent effects are obtained by using
different colours for the two coats, as suggested, and stippling the
second, while wet.
Space will not permit of a more lengthy reference to this part of the
subject, but full information can be obtained from Mr. Miller's book
already mentioned. Something should be said, however, about
BRUSH GRAINING,
because it is so very well suited for work of this character, and by
its use some very pleasant effects may be produced.
[Illustration: Fig. 116.--SHOW CARD DONE BY SPRAYING.]
[Illustration: Fig. 117.--ANOTHER EXAMPLE.]
In this case, a material such as "Matsine," or "Scumblette" is applied
by spraying over a different coloured ground, and, while wet, this is
"flogged," or a dry brush is drawn over the surface, removing hair-like
parts which expose the ground colour beneath. Thus a very dark green
or even black may be used over a white or nearly white ground, or a
very dark red over an orange chrome ground. Various metallic effects
may also be produced on wood or other materials by using silver,
aluminium, gold or copper leaf, and partly spraying over it a lacquer
of suitable colour.
The actual graining can be done in the ordinary way by an expert
artisan, but as a rule this would be too costly when perhaps thousands
of iron or other goods are to be turned out in a short time. In such
a case transfer graining paper is sometimes employed, but this also
is somewhat costly. Bellamy's graining rollers are found to be very
economical. This tool consists of a cylinder on the outside of which
is engraved the grain of various woods, such as oak, mahogany, maple,
satin wood, birch, walnut and ash. All that is necessary in working
it, is to pass the roller over the surface immediately after the
graining colour has been applied, when it will be found to remove some
of the paint and give the appearance of graining. This appearance is
considerably enhanced if the parts are softened after the roller is
used by going over the work with a badger softener.
MARBLE GROUNDS.
For the convenience of those who are called upon to imitate marble for
any class of work, the following information is given as to the colours
to be employed for the ground colours.
WHITE.--A dead white ground should be used mixed to dry hard and smooth.
SIENNA.--White blended with a mixture of white and raw sienna in
irregular patches.
PINK MARBLE.--The ground may be the same as that used for sienna, but a
little Venetian red should be added to give it a pinkish cast.
ALABASTER.--Light cream ground made by adding a little middle chrome
and vermilion to white.
ROUGE GROTTE.--This is a very beautiful marble which contains a large
number of different colours. The ground may be either white or Venetian
red, mixed with a little chrome yellow.
GRANITE.--There are several varieties of granite, the principal being
termed "grey" and "red" respectively. To mix the former ground, add
a little black and Prussian blue with just a touch of Indian red to
white. The grounds for red granites can be produced by mixing Venetian
red and white.
ROUGE ROYAL.--A mixture of Indian red, Venetian red and vegetable
black, with a little white, will make the correct colour for the ground
of this beautiful marble. It is very necessary that the ground be
quite "solid," and to produce this, two, or even three, coats may be
necessary.
EGYPTIAN GREEN.--The ground should be a dead black.
VERD ANTIQUE.--The same as above.
DEVONSHIRE MARBLE.--Venetian red and ochre with a little white to
produce a light terra-cotta ground.
BLACK AND GOLD.--A dead black ground should be used.
DOVE.--In this case a white ground without gloss may be employed, but
a grey is better, such as that produced by tinting white with Prussian
blue, a little black and a very little Indian red.
GREY.--The same as "dove."
ST. ANNE'S--A dead black ground should be used.
GRAINING GROUNDS.
POLLARD OAK.--The ground colour is prepared with a mixture of Oxford
ochre, Venetian red and white lead in proportions, to form a rich buff;
or white lead, chrome yellow and vermilion may be used.
KNOTTED OR ROOT OF OAK.--This ground is exactly the same as the above.
BIRCH.--The ground is prepared with white lead, a little Oxford ochre
and a little Venetian red, of which latter, however, only sufficient
must be used to make a very light buff colour.
MAHOGANY.--The ground colour is prepared with the best Venetian
red, yellow ochre and a little white lead (or orange chrome may be
substituted for the yellow ochre). If it is desired to increase the
brilliancy of the colour, substitute vermilion for Indian red. If a
light ground is required use the same colours as above, adding more
white. The addition of a little vermilion will increase the richness of
the colour.
ROSEWOOD.--The ground colour is mixed in the same manner as above
described for mahogany, but a little burnt Turkey umber and Victoria
lake is added.
SATINWOOD.--A little Oxford ochre added to white lead gives the proper
ground for this wood.
[Illustration: Fig. 118.--SHOWING THE BEAUTIFUL SHADED EFFECTS WHICH
MAY BE PRODUCED BY SPRAYING (STRONG).]
WALNUT.--The ground is prepared with white lead, Venetian red and
Oxford ochre, with a small quantity of burnt Turkey umber, but not so
much as to destroy the appearance of the other colours and make them
poor. Neither red nor yellow should be in excess, but all should
be toned down with the umber. Although this colour may look dull when
mixed, it is only a relative dullness, and it will shine out brightly
enough when grained and glazed.
BIRD'S EYE MAPLE.--This ground may be prepared with either white lead
and a little Oxford ochre, Venetian red or vermilion, but care must be
taken not to use too much.
SATINWOOD.--The ground should be a yellowish white, obtained by adding
yellow ochre to white lead.
NOTE.--Those who desire to obtain copies of marbles and woods printed
in colour, from which to copy, should obtain either or all of the
following books:--"The Art of Graining and Marbling," by James Petrie.
Price 25s. The Trade Papers Publishing Co., Ltd., 365, Birkbeck
Bank Chambers, High Holborn, London, W.C.; "The Art of Graining,"
by W. Sutherland. Price 25s. A. M. Sutherland, 26, Oxford Road,
Chorlton-on-Medlock, Manchester; "Graining," by A. R. Van der Burg,
26s., Crosby Lockwood and Co., Stationers' Hall Court, London, E.C.
In Fig. 119 is given an illustration of a fruit dish, the ornamentation
of which has been done by spraying. In Fig. 120 is shown a portion of a
table cover done by the "Airostyle" on a fine art fabric.
There is, of course, no limit to the number of artistic designs which
may be produced by applying the paint by compressed air; indeed, the
air brush or spraying machine for this class of work produces results
which cannot be obtained in any other way. Several of the engravings
illustrate forms of advertising cards all done by spraying, while
Fig. 118 illustrates very well indeed the different effects in form
which may be produced by the spray properly used, such as the raised
panels, the sphere in the middle and the convex and concave portions
of cylinder. These examples are reproduced, with full acknowledgments,
from the "Book of Designs" by Chas. J. Strong, of the Detroit School of
Lettering, Detroit, Mich., U.S.A. The price of this book is £1 ($5.00),
and it contains an immense number of useful designs suitable for the
use of sign painters, show card writers and commercial artists. It may
be had in London from the office of the "Decorator," 365, Birkbeck Bank
Chambers, London, W.C.
CHAPTER XIII.
THE "FLOWING-ON" SYSTEM.
The very latest method of finishing automobiles which have steel bodies
is that at present in use by the Ford Motor Co., Ltd., at Trafford
Park, Manchester, and elsewhere. The method is a remarkable one not
only because of the great saving of time it effects, but by reason
of the fact that the "life" of the painted or enamelled surface is
prolonged by the improved method.
Stated briefly, the process consists in coating the body with
blue-black enamel by means of gravity only; that is to say, the enamel
is placed in an elevated tank and discharged on to the work through a
flexible pipe and slotted nozzle opened by a lever which is actuated by
the thumb of the operator. Thus no spraying is required, while dipping
is out of the question, as only the outside of the body is required to
be painted.
Each coat takes two minutes to apply to the whole surface of a
four-seated Ford motor body! An achievement which justifies our use of
the word "remarkable."
But it will be convenient to explain how the present method came into
use. Until a few months ago the several undercoats were sprayed on the
work in the ordinary manner, but the finishing coat of varnish was
flowed on by the gravity apparatus now referred to. Then it was thought
that the undercoats might be applied by the same method, and some
careful experiments having been made, it was found that by dispensing
with the spraying and flowing on the coats a much more satisfactory
result was obtained. As the new method caused more paint to adhere to
the work than would be put on by the spray under ordinary conditions,
one coat, it was found, could be dispensed with altogether. There
was also less rubbing down required because of the very smooth coat
obtained by flowing on, and, above all, the time of applying the coat
was reduced to the extraordinarily short time of two minutes.
[Illustration: Fig. 119.--A CHINA FRUIT DISH DECORATED WITH THE
AIROSTYLE.]
[Illustration: Fig. 120.--TABLE COVER DECORATED WITH THE AIROSTYLE.]
The apparatus employed for this work is of the simplest character.
The car body is placed upon a platform mounted upon wheels. This is
made of exactly the right size to fit between a V-shaped metal trough
which surrounds three sides of the body and is intended to receive the
superfluous paint, a considerable quantity of which drips into it from
the body as the enamel is applied. This trough, a sketch of which is
shown in Fig. 121, is slightly inclined so that the paint which drips
off all runs to one point, where it passes through a gauze covered
orifice, descends to a small tank beneath, whence it is pumped up to
the elevated tank above and is then ready to be used again.
This elevated tank is cylindrical and holds, perhaps, 25 or 30 gallons.
It is stationed overhead some 12 or 15 feet high. From this tank
descends a flexible metal pipe or hose ending in a slotted nozzle,
opened by a lever, which is operated by the thumb of the workman and is
closed by a spring. This completes this simple though very effective
apparatus.
The body of the car is made of stamped steel which has already received
a protective coat of paint of a dull red colour, the body being placed
upon the platform or bogie and being placed in position with the
V-shaped trough surrounding it on three sides. The first or undercoat
is given by rapidly passing the slotted end of the lever valve over
the surface, upon which the paint literally pours out. The top part
receives attention first and the paint runs down over the surface,
which it covers completely, excepting perhaps here and there, where the
discharge of paint is directed, and the whole of the outer surface of
the car is, as already stated, completely covered in two minutes. This
coat dries semi-flat.
In order that the discharge pipe may be kept nearly vertical and be
moved around the car as the different sides are dealt with it is
provided, at its upper end close to the point where it joins the tank,
with a brass swivel union and a horizontal arm which swings around. A
stop-cock is also provided.
The undercoat having been applied the body is allowed to rest for a
few minutes until the dripping ceases. It is then wheeled on the bogie
across the room to an oven, in which it remains for one hour at a
temperature of 160° F. This heat is found to be sufficient to bake the
paint but is not high enough to injure the woodwork which, of course,
forms part of the body. At the expiration of the hour a little stopping
of inequalities of the surface is usually found necessary, but in any
case the surface is lightly rubbed down with fine glass paper.
[Illustration: Fig. 121.--SKETCH OF TROUGH TANK USED IN FLOWING ON
PAINT.]
The body is now brought underneath a second tank with the V-shaped
surrounding trough exactly as before described, and here it receives
another coat of enamel or paint, which in this case has a little more
body and gloss. After stoving as before and at the same temperature the
surface is carefully but rapidly rubbed down with powdered pumice stone
and water applied by means of felt pads.
There are a series of four troughs and tanks in all, corresponding
in number with the coats to be applied. From the third one the body
receives a third coat, is then baked or stoved, rubbed down with
powdered pumice and water, thoroughly cleaned off, and from the fourth
tank receives the final coat of varnish which completes the operation.
This coat of varnish is not stoved but is air-dried. The finish is a
blue-black picked out with very dark blue, and it is free from any
signs of runs or drips; in fact, no one could tell how the application
was made. As already remarked, the coats of paint are somewhat fuller
than would be the case if they were applied by spraying, and the
durability is thereby increased.
The output from this department is 70 cars a day, a number which would
be practically impossible if the work were not so splendidly systemised.
It should be observed that the varnish is applied in a separate room
from that used for the application of colour. This is done in order to
exclude dust, and also to maintain the temperature at 90° F.
In considering the essential points of this method of finishing motor
bodies, it is clear that the system might be successfully applied in
very many other industries to a great variety of goods. The apparatus
is so simple in character that no engineer would have the least
difficulty in designing a plant suitable for any particular requirement.
It must be admitted that the crux of the whole situation is the kind
of paint or enamel used. It must be sufficiently viscid to hold on to
the surface to which it is applied, sufficiently liquid to run off
freely without leaving runs, tears or "fat edges." And, above all, it
must flow out uniformly. All these conditions, however, apply also to
a dipping plant, and only require careful consideration on the part of
the paint manufacturer who has made a special study of the subject.
The varnish applied by this method must also be of a special character
so that it may flow out nicely without yielding too thick a coat,
which would be likely to lead to blemishes. Ordinary paint, enamel or
varnish, then, will not answer for this class of work, but special
products must be employed, and when these are obtained, the rest is
comparatively easy.
THE FLOCO PROCESS.
This process is in some respects similar to that above mentioned, the
difference being that it is intended principally for the application of
varnish by flowing over a painted surface done by spray. The essential
difference in the apparatus is that the varnish, instead of being
discharged by gravity, is pumped up from a tank. It is largely used in
America, and is manufactured by the DeVilbiss Manufacturing Company,
Toledo, Ohio, U.S.A. It is particularly suitable for automobile bodies
and large surfaces generally.
The process flows such materials as varnishes, enamels and japans, when
it is impracticable to spray them. It has superseded the inadequate,
inefficient flowing systems used in the past, and is also replacing
brush and dip methods as practised in many instances.
The equipment of the process comprises a 15-gallon tank, drawn from one
sheet of steel and heavily tinned; 1-6 H.P. motor, housed in, driving a
rotary pump; regulator; nozzle; electric fittings; flexible fluid hose,
and galvanized iron drain trough on rack. All parts, excepting nozzle,
hose and trough, are mounted on a castered truck for moving about. The
truck is equipped with a rack around which to wind the hose when not in
use, and a holder for the nozzle.
[Illustration: Fig. 122.--THE "FLOCO" SYSTEM OF PAINTING MOTOR BODIES.]
[Illustration: Fig. 123.--SHOW CARD DONE BY SPRAYING (STRONG).]
The finishing material, such as varnish, to be used is pumped from the
bottom of the tank by the electric motor-driven pump, in a continuous
stream, through the flexible hose, to the nozzle. The flow of material
is adjusted by the regulator, by means of which a varying amount is
not put into use and returned to the tank. In this way the flow from
the nozzle is instantly adaptable to any class of work and viscosity of
fluid without changing the speed of the motor.
When the nozzle is closed the material pumped is all forced back into
the tank through the overflow. This, serves to agitate the material; in
fact, is the only agitation necessary with material containing pigment,
such as colour varnish.
The body to be flowed is--as shown in Fig. 122--placed over the drain
trough. The operator first applies the material all along the top,
then flows it copiously over the upper half of the surface. Sufficient
material is thus, applied to insure a perfect flow to the bottom. The
job is allowed to drain into the trough which carries the material back
to the tank--here it is strained and, without the slightest waste, used
again.
Only enough material is put into the tank to take care of the work at
hand, or to handle the day's production. The maximum amount of material
exposed is 15 gallons--the tank's capacity. The nozzle will operate
satisfactorily on a gallon of material.
The tank, motor, pump and regulator are--as previously stated--mounted
on a truck fitted with casters, permitting of these parts being moved
about with the greatest of ease. Another appreciable advantage of this
style of arrangement is that an extra truck can be kept on hand and put
into immediate use in case of accident.
The cleaning of the parts is simple. The nozzle of the machine is
detached and all of the material pumped out of the tank, after which a
small quantity of naphtha--or some other similar solvent--is put into
the tank and pumped through the machine.
As the motor is only 1-6 H.P., the consumption of power is low. The
motor is made for all kinds of current, and can be attached to any
light socket.
It may be observed that the pressure tank used in this equipment
permits of the use of heavier or more viscid enamels and paints than
would be possible where gravity was depended upon. In view, however,
of the success which has been met with in the case of the Ford Motor
Company, there appears to be no reason why the Floco process should not
be used for some of the undercoats, as well as for the finishing.
The following article by M. C. Hillick appeared in "The Painters'
Magazine," of New York, and will doubtless be read with interest:--
The Willys-Overland automobile factory has recently been installed with
sixteen large enamelling furnaces or ovens having a volume of 48,000
cubic feet and a capacity of 140 tons of enamelled product every ten
hours. These ovens have been electrified and they require approximately
5,500 horse-power. For some months past the Overland Company has been
testing one of these electrically-heated ovens, and the results have,
in every way, measured up to expectations. Formerly the company, in
common with practically all other companies using enamelling or baking
ovens, employed gas as the treating medium. The ovens now electrified
are almost entirely automatic in operation. When the oven is loaded the
closing of its doors automatically throws a switch which turns on the
current. A pyrometer which can be adjusted to operate at any desired
temperature rings a bell when the proper degree of heat is reached,
thus notifying the attendant, and also automatically turning off the
current. The electrically heated oven does away with all flue gases
and with their attendant dirt and spots. It also reduces the required
volume of ventilation to the minimum, thereby eliminating air currents
and the dust which, in greater or less degree, usually accompany them.
The electrification of the ovens does away with explosions, banishes
danger from fire, and gives an assured "safety first" to the workmen.
The heat is said to be non-oxidizing and, therefore, cannot scald the
operator. The working quarters are rendered comfortable and a higher
grade of work is made possible.
[Illustration: Fig. 124.--SHOW CARD DONE BY SPRAYING (STRONG).]
While for the custom shop painter it is a long way to such equipment,
the fact that these facilities are gradually being acquired leads
to the assumption that, in the course of a few years at most, some
portion of the work coming to the shop for painting repairs will be
handled through the baking oven. In connection with this subject of
enamelling and oven baking, the various costs of paint and varnish,
it is to be noted that the excessive temperature employed in baking
is being criticised as detrimental to the finish. Recent tests are
said to have been made which show that baking paint and varnish at the
maximum temperature shortens the life of the finish. Mr. J. W. Lawrie,
of the Chemical Works of Milwaukee, Wis., has stated that, as a rule,
the lower the temperature and the longer the time the paint and
varnish is baked, the finer the appearance, service and durability of
the finish and the greater its capacity for resisting moisture. The
finish will have more elasticity and deeper lustre. Mr. Lawrie is of
the opinion that twelve hours at 180 degrees are better than five hours
at 280 degrees.
In some motor car shops, within the past two years, by the use of
baking ovens cars were painted and finished, all coats being baked, and
made ready for service in three days. However, we are not commending or
recommending this practice. For the custom shop painter, especially,
it is entirely unsuited. Nor would we recommend the baking process
for surfaces other than metal. The same disadvantages marshalled in
opposition to baking paint and varnish upon wood surfaces fifteen
years ago, or longer, still remain in evidence. For aluminium, sheet
steel or other metal panels or metal surfaces in general, the baking
process offers an opportunity for finishing work under conditions more
uniform than any which may be expected to prevail outside the oven.
An other advantage is noted in favour of oven baking. It permits the
use of more elastic materials without the aid of artificial oxidizing
agents. As compared to the present air-drying system, the oven baking
method, operated upon a conservative basis, permits the car to be
thoroughly painted and finished in six or eight days. The use of more
elastic materials--paints, colours and varnishes--has been mentioned as
a part of the oven baking method. Upon steel surfaces this is perhaps
more necessary than upon aluminium, and possibly iron. Steel has a
linear expansion double that of wood. As a matter of fact, experts in
these matters employed by the Pennsylvania Railroad assert that the
contraction and expansion of steel surfaces is much more pronounced
than the same action in wood. Materials of greater elasticity as
compared to those used in natural air-drying practice are urged.
Primers and surfacers, and the general class of foundation coats, will
require an average of three hours' baking at 200 degrees F. While some
colours require higher degrees of heat than others, 170 degrees F.
baked for, say, six hours will dry the average colour, excluding white.
The latter pigment, baked at a temperature varying from 85 to 110
degrees F., will dry properly in the course of a few hours, and retain
its natural purity of colour, whereas at a higher degree of heat the
white takes on an objectionable yellowish cast. Black, at the opposite
end of the colour pole, can be safely baked for six hours, at something
like 200 degrees F. Finishing varnishes, taking them as they run, will
bake at from 110 to 150 degrees F. for five or six hours. In all baking
practice the personal equation figures largely. Reason, good judgment,
the capacity for taking pains--all these are items of importance.
Oven baking methods are being successfully employed in some of the
large city repainting establishments. A firm near New York, for
example, using what is known as the radio process, paints and finishes
a car in three days. The cleaning of the cars is accomplished by the
use of a steam jet, a treatment which is said to cut away the grease
like magic. All surface defects following the cleaning of the car are
touched up and faced over with the necessary filling and surfacing
materials. Then these patched-up parts are rubbed down with water and
rubbing brick, and the general surface of the car is lightly rubbed
with pulverized pumice stone and water. All colour, and varnish
colour, coats are applied with a paint atomizer. This atomizer is
a pistol-shaped device operated with a trigger, the material being
sprayed from the muzzle of the barrel. The varnish colour is baked for
three hours at a temperature of from 110 to 120 degrees. From 90 to
100 degrees of humidity are provided for the oven, and by means of an
exhaust fan a fresh supply of air is furnished every three minutes.
In the oven where the varnish colour coats are baked a thermostat is
installed, which regulates the temperature. All the air entering the
oven is washed and purified by running it through a water tank before
it enters the oven. This water-washed air is forced into the oven by a
fan blower, and contact with a radiator superheats it.
In practice, the high humidity here referred to, and the water-washed
air, are mediums which serve to keep the outer surface of the drying
coat moist while the inner surface is drying, in this manner furnishing
in due time a paint film dried uniformly from top to bottom.
The finishing varnish is dried in an oven having a maintained
temperature of from 90 to 100 degrees, the humidity being regulated
at from 60 to 70 percent. This humidity is likewise found to assist a
varnish film to dry uniformly throughout.
[Illustration: Fig. 125.--DESIGN FOR SHOW CARD (STRONG).]
The treatment of the car chassis in the establishment here referred to
is quite similar to that given the body of the car. A steam treated
potash bath is provided into which fenders and other removed parts
are immersed, removing all grease and foreign substances, and even the
paint, from such parts. These parts, after cleaning, are then dropped
into tanks containing the required paints, varnish colour, etc., after
which they are taken out and drained and then consigned to an oven
maintained at a uniform degree of heat.
Other establishments having ovens installed are employing methods
designed to secure equally quick results without sacrificing any
measure of durability or appearance.
In the absence of ovens, not a few car and carriage painters are
practising the so-called hot-air method as far as possible. Successful
results are reported in many instances, the work being turned out
quicker, with an increase in lustre advised in some cases. This method
is very simple and requires no previous experience or special training.
Anyone capable of providing the necessary degree of heat--85 to 95
degrees F.--and maintaining it for eight or ten consecutive hours, can
have the benefit, in full measure, of the hot-air system. Coats of
paint, colour, varnish colour and varnish dry rapidly in a temperature
at the above degree, where the ventilation is good and a fair volume of
pure, fresh air can be constantly brought into the drying room.
NOTES ON THE CONSTRUCTION OF STOVES.
The construction of stoves for use in connection with enamelling
and baking japans generally does not properly form part of this
treatise, but a few remarks on the subject may be of service. It is
to be regretted that in only too many cases the stoves employed are
very inadequate. In some cases they are heated by gas, and the jets
cause a certain amount of discoloration. This is objectionable even
when the work is black, but if it is coloured it may lead to serious
disadvantages. In Fig. 126 is shown a sketch of what is known as the
"Perkins System of Heating." It is largely adopted in many trades for
enamelling cycle frames and parts, lamps and motor horns, etc. It is
this system which is used by Messrs. Lucas, Limited, of Birmingham, a
description of whose plant is given elsewhere. In the "Perkins" system
water is heated under pressure, and the comparatively high temperatures
required for drying and other similar purposes are obtained in a simple
but efficient manner.
The apparatus consists of circulations of hydraulic tubing, certain
proportions of which are formed into a coil and placed in a furnace
situated in any convenient position outside and below the drying
chamber. The apparatus is hermetically sealed and self-contained,
the heating water circulating from the furnace through the heating
pipes or coils and back again to the furnace without any loss through
evaporation. No pumps or moving parts of any description are required,
so that unskilled attention only is needed.
[Illustration: Fig. 126.--THE PERKINS STOVE.]
The illustration shows a simple application of the apparatus, which is
the type often employed for cycle and motor parts, bedstead frames,
electric apparatus parts, etc. The arrangement of the pipes, of course,
depends upon the class of work which has to be dealt with.
[Illustration: Fig. 127.--A TYPICAL GOODYEAR STOVE.]
[Illustration: Fig. 128.--DIPPING TROUGH.]
In Fig. 127 is shown a type of stove manufactured by Goodyear and Sons,
Churchfield Works, Dudley. The construction is a great improvement
on the old-fashioned type of enamelling stoves, which through
faulty design were responsible for great loss through radiation and
combustion. The work done in such stoves is necessarily inferior. The
firm named are among those from whom may be purchased up-to-date stoves
heated by gas (ordinary lighting or producer), steam, superheated
water, and oil, either single, double, or treble cased suitable for
purposes which a few years back were hardly dreamt of, and which may be
said to range from hairpins to bedsteads, and include munitions of war,
such as stoves for shell drying and varnishing. A very important part
of the process of stoving is the rack and trolley system of transport
in and out of the stove, which in effect means that no article is too
heavy for such process. In the production of stoves for enamelling
certain firms have made a special study of the requirements, including
those above mentioned.
[Illustration: Fig. 129.--SHOW OR MENU CARD (STRONG).]
[Illustration: Fig. 130.--EXAMPLE OF METAL DECORATION--LID OF COAL BOX
DONE WITH AIROSTYLE.]
CHAPTER XIV.
LIME AND WHITEWASH SPRAYERS.
As explained in previous chapters, this type of machine is of an
entirely different and much simpler construction than those used for
spraying oil paint, varnish, etc. Yet such apparatus is used to a very
considerable extent in factories of all kinds as well as for spraying
insecticides on fruit trees and other purposes of the agriculturist. By
the Factory and Workshop Act of 1901 it is provided that "all walls and
ceilings must be limewashed at least every fourteen months, and painted
and varnished work must be washed with hot water and soap at the same
periods. Special exceptions to this rule may be made by Special Order."
Such an order was made in 1911, which was to the effect that "when
at least two coats of washable water paint or sanitary distemper is
used instead of limewhite the period for renewing with one coat of
such paint shall be three years. The paint, however, must be washed at
least once in every three months. It is provided in this Order that
"If it appears to an inspector that any part of a factory to which
the exception applies is not in a cleanly state, he may, by a written
notice, require the occupier to limewash, wash or paint the same; and
in the event of the occupier failing to comply with such requisition
within two months from the date of the notice, the special exception
shall cease to apply to such part of the factory. In this Order a
washable water paint means a washable paint which, when finished for
use contains:--(i) at least half its weight of solid pigment containing
not less than twenty-five parts by weight of zinc sulphide as zinc
white (lithopone) in each hundred parts by weight of solid pigment and
(ii) at least ten parts by weight of oil and varnish to each hundred
parts by weight of solid pigment."
It should be stated that the type of machine now under consideration
may be used for the application of such paint or distemper provided
that it is rendered sufficiently thin by the addition of water. If very
thick compressed air will be required as in the case of ordinary oil
paint.
An excellent machine for applying limewash, whitewash or distemper is
made by Messrs A. C. Wells and Co., Engineers, London and Manchester.
It is used to a very large extent by engineers and in factories,
breweries, car sheds, cattle docks, etc. Builders, decorators,
corporations, etc. also find it of great service for special work.
The manufacturers state that over 5,000 of these machines have been
sold, and that they are fast taking the place of the old method of
limewashing with the brush. The speed with which lime, whiting or cold
water paint can be applied is from 10 to 20 square yards per minute.
A very distinct advantage of the machine over brushes is that when an
irregular surface, such as a brick wall, the joints of which are not by
any means perfect, is being dealt with, the lime or distemper is forced
in by the spray into the interstices which could not be reached by
the brush. These machines consist essentially of a pump with spraying
nozzle which is made in various forms, the simplest of which is that
shown in Fig. 131.
[Illustration: Fig. 131.]
[Illustration: Fig. 132.]
This machine is designed to stand rough usage. The pump is simple
and easily removable for repairs, and the spraying nozzle, which is
naturally an important feature, can be regulated to any degree of
fineness. A patent filter is provided which prevents clogging. It will
be observed by the illustration that wheels are provided which enable
the machine to be easily removed from one place to another. A 15 ft.
armoured delivery hose and 5 ft. spraying pole for reaching the upper
portion of a surface to be sprayed is provided. The capacity is 8
gallons. The machine shown in Fig. 132 is somewhat smaller and cheaper.
It contains 6 gallons.
[Illustration: Fig. 133.]
[Illustration: Fig. 134.]
Fig. 133 shows a machine with a double spraying nozzle and valve
arrangement. This has several advantages over the single pattern; the
speed is almost double, and one jet can be put out of action if desired
when working in cramped places. It is a powerful machine with 12 gallon
tank and strong lever pump. It is supplied with large wheels and is
easily moved about, and is eminently suitable for anyone having a large
quantity of work to do quickly.
In dealing with very high buildings either the single or double nozzle
is attached to a bamboo pole, as shown in Fig. 134.
[Illustration: Fig. 135.--THE BROWN SPRAYER WITH EXTENSION ROD.]
In Fig. 135 is shown an excellent machine suitable for spraying
whitewash, distempers and disinfectants. It is manufactured by the E.
C. Brown Co., of Rochester, N.Y. The pump is of a simple but effective
character; the valves are located so that they can be opened instantly
and are fitted with springs so that the operator can pump while the
machine is pointed in a downward direction. The strainer has five
inches of screen surface and the screen can be instantly removed and
cleaned. The pump barrel projects beyond the hand and serves as an
extension rod. The nozzle is guaranteed not to clog, and is fitted
with Messrs. Brown's patented screen arrangement. It throws four
different kinds of spray, one a solid stream, the second a broad
carrying spray, the third a long driving spray for ceilings and tops
of walls, and the fourth a fine spray which may occasionally become of
service for spraying work near at hand.
There are several other makes of machines suitable for whitewash
spraying, among them one manufactured by Merryweather and Co.,
Greenwich Road, S.E., The Bean Spray Pump Co., Los Angeles, California,
U.S.A., and the Four Oaks Spraying Machine Co., Sutton Coldfield,
Birmingham. The last named is particularly well adapted for spraying
insecticides upon fruit and other trees.
[Illustration: Fig. 136.--THE MERRYWEATHER LIMEWHITE SPRAYER.]
[Illustration: Fig. 137.--A TUMBLING BARREL.]
[Illustration: Fig. 138.--ANOTHER FORM.]
THE TUMBLING BARREL PROCESS.
This process of japanning small castings is very successful in those
cases where the parts are small and intricate in construction, and,
therefore, cannot either be dipped or sprayed, excepting with some
difficulty. The great advantage of tumbling is that such work is done
better and faster than by dipping. A machine, of which two examples
are shown in Figs. 137 and 138, is used in this process. Inside this
machine are placed a number of shot or steel balls of different sizes.
The articles to be treated are then introduced in the japan and the
machine is started at varying degrees of speed. The shot carries the
japan over the various parts and into the interstices. As different
objects and materials require different speeds, some work will be
started slowly and the speed increased to get the desired finish.
The objects are then dumped out on to wire screens or baskets, and
shaken, when the steel balls and shot fall through the mesh, leaving
the articles that have been japanned behind. The baskets are then hung
in baking ovens, while the balls are washed in gasoline ready for use.
The machines mentioned above are manufactured by the Baird Machine Co.,
Bridgeport, Connecticut, U.S.A. The English agents are R. Cruickshank,
Ltd., Camden Street, Birmingham.
CHAPTER XV.
A PORTABLE PAINT SPRAYER FOR RAILWAY AND OTHER WORK.
Mr. M. E. McDonnell, Engineer of the Pennsylvania Railroad Company,
Altoona, Pa., U.S.A., very kindly furnishes the author with the
drawings which will be found on the following pages. He says:--The
Company does very little painting by dipping. The spray process is,
however, used very extensively, a large percentage of our freight
cars having been painted by this method for years. The method is very
satisfactory and also economical. The saving in the cost of labour in
the spraying method is approximately 60 per cent. In some cases the
saving is greater than this. In one of our largest shops the cost of
application per unit for a given number of square feet is thirty-eight
and nine-tenth cents with the spray as compared with one dollar with
brush. It might be said that more paint is applied per coating when the
brush method is used. A given surface which would require 10 gallons of
paint for one coat by the brush method would require approximately 7
gallons by the spray method.
When painting a freight car a more uniform coating is obtained when
the brush is used, due to the fact that the paint can be brushed out
behind ladders and other things which would obstruct spraying, while in
the application of the paint with a sprayer it is necessary to apply
a thicker coating at certain points in order to reach other points
which are obstructed, and which must, therefore, be approached from a
side angle. The spray however, reaches certain crevices which cannot
be reached with the brush, which is in some cases advantageous with
the painting of freight equipment cars. Our Company would not consider
returning to the brush method of painting.
The machines which we use for spraying the paint are made in the
Company shops.
The following is a description of the apparatus referred to:--
It consists of a stout steel cylindrical receptacle 11½in. internal
dia. by 24in. in depth, and having a capacity of about 12 gallons. It
is supported on a special wheelbarrow of wood with trundling wheel of
cast iron. The bottom of the receptacle is so low down that it rests
on the ground when in use, by lowering the handles of the barrow. The
paint is placed in this cylinder and is forced out by air pressure,
introduced through the lid of the receptacle, at from 80 to 90 lbs.
pressure per square inch. This air is provided from the shop compressor
range or by a separate compressor. The paint pipe penetrates the
cover and is extended nearly to the bottom of the receptacle. The air
pressure on the surface of the paint forces it through this pipe to the
atomizer.
A branch from the air supply is also taken to the atomizer and a third
air branch taken to the bottom of the receptacle and carried through
a 1in. iron pipe stopped at the end with a screw plug, but perforated
with a number of 1/8in. holes. This latter is for agitating the paint
and prevents settlement. The atomizer is shown clearly in the drawing.
It consists of an air jet impinging on a vena contracta nozzle and
surrounded by the paint forced through from the receptacle. The air
blast carries the paint through the orifice immediately opposite to the
nozzle and there reduces it to a fine spray. A hose is attached to the
exit of the atomizer and the atomized paint is carried by the blast to
the spray pipe, which is slightly fan-shaped and flat.
The cover is fastened by four hook-clamps, and is, therefore, readily
removable. An air pressure gauge reading to 120 lbs. is also provided,
and the valves are so arranged that the regulation of both the paint
and the air supply are easily adjustable.
It will be noticed that, in the atomizer, a vena contracta is
arranged so that it may be adjusted in its position in relation to
the air orifice. The use of this is to provide for paint of various
consistencies. Very great care has been taken in designing the details;
as, for example, the provision of a scraper to clear off accumulations
from the periphery of the trundling wheel.
[Illustration: Fig. 139.--PLAN OF PAINT SPRAYING APPARATUS USED BY THE
PENNSYLVANIA RAILROAD, PRINCIPALLY FOR FREIGHT CARS.]
[Illustration: Fig. 140.--ELEVATION OF APPARATUS SHOWN IN FIG. 139.]
[Illustration: Fig. 141.--DETAILS OF APPARATUS SHOWN IN FIGS. 139 AND
140.]
CHAPTER XVI.
METAL SPRAYING.
Although the spraying of metal does not really come within the scope
of this book, the process is so closely allied to paint spraying
that it is considered advisable to devote a chapter to the subject,
particularly as the perfected process is of very recent date, and bids
fair to be used successfully in many industries. It should be stated at
once that a metallic coating may be applied to practically any surface,
and that almost any metal or alloy may be employed.
Stated briefly, the process consists in melting metal in the form of a
rod or wire, by means of oxygen and coal gas, or other gas, depending
upon the metal used. The molten metal is sprayed at a high pressure,
and a surface may be quickly covered with the metal of any desired
thickness. A remarkable fact concerning the process is that the metal
is cooled to an extent that renders it possible to hold the hand in the
jet so as to receive a coat of metal without inconvenience, and samples
of wood and fabrics may be coated with metal without injury.
A moment of consideration will render it clear that there is an immense
field for this process; for example, as aluminium can be sprayed, a
lining of that metal might be given to brewers' and cooking utensils,
etc., while tanks, barrels, reservoirs, intended to contain acids and
oils, can also be treated. In the production of blocks for printing,
in decorative work and mural decoration, there is an immense field,
while ships' bottoms, instead of being painted with composition, can
be copper-plated or sprayed with any other suitable metal, in order
to prevent incrustation. No doubt some very beautiful effects can be
produced by means of the process.
It will be convenient now to describe the machine used for the
application of the metals. It consists of a pistol rather bulkier, but
not unlike in form, the usual spraying apparatus, see Fig. 142.
[Illustration: Fig. 142.--THE METAL SPRAYING MACHINE OR "PISTOL."]
[Illustration: Fig. 143.--THE METAL SPRAYER.]
In Fig. 143 is shown very clearly the construction of the sprayer,
which it will be understood comprises a combined melting and spraying
jet and a feed mechanism. The metal, in the form of rod or wire, is
fed to the melting flame. This, as already stated, is formed by coal
gas burned in the air, or oxygen, water gas, acetylene, hydrogen,
etc., may be employed instead of the coal gas. The gases are supplied
at such a pressure as to prevent blowing out and to ensure a highly
deoxidizing flame. The spraying jet can be of carbon dioxide, nitrogen,
air, steam, etc., and it must be fed at such a pressure as to produce
a sufficiently high velocity for successful coating. The usual gauges
and reducing valves will, of course, be employed. The feeding of
the wire is accomplished by a small pneumatic motor, driven by the
spraying medium, either in series or parallel with the main jet.
The dimensions of the wire nozzle, and feed mechanism vary with the
different metals. To obtain a good adhesion between the metals being
sprayed and the surface to which it is to be applied, the latter must
be thoroughly clean and of an open nature, to give a key for the
deposit. Sandblasting is sometimes employed to effect this.
Fig. 145 shows an enlargement of the nozzle with the different parts
marked. The cost of the process is not prohibitive; the cost of the
metal only on one square foot of a thickness of 0·001 inch is quite
small with the cheaper metals. The process is put on the market by the
British Metal Spray Co., Ltd., Queen Anne's Chambers, Tothill Street,
Westminster, London, S.W.
In a paper read by Mr. R. K. Morcom before the Institute of Metals, the
following interesting information was given:--
[Illustration: Fig. 144.--SECTIONAL DRAWING OF THE METAL SPRAYING
MACHINE OR "PISTOL."]
With a given design of jet there is only a certain volume left by the
air-jet which can be filled with flame, and this flame has a limiting
temperature which cannot be exceeded. The wire, passing through this
cone of flame receives heat, partly by radiation, but chiefly by
conduction, and becomes melted; but there is a definite limit to the
amount of heat which can be picked up by the wire passing through the
flame, and a definite limit to the rate at which it can be melted. This
cannot be increased by forcing more gas into the flame, as the extra
gas is merely blown away by the air-jet. It is possible to increase the
rate of melting by shaping the nozzles so as to leave room for a larger
cone of flame, and experiments are in progress on this point. There
is, therefore, a most definite economical quantity of gas which should
be used in the pistol, this quantity being about 1·5 cubic foot of
hydrogen per minute, and 0·5 cubic foot of oxygen; or about 0·8 cubic
foot of coal-gas to 0·65 cubic foot of oxygen for the present standard
designs.
In refractory metals these quantities may be increased slightly, as
a slightly higher temperature can be obtained if the burning gases
are under a pressure greater than atmospheric, and this occurs if the
gas quantities are increased, the inner surface of the air-jet acting
to some extent as an enclosing wall to the flame. On the other hand,
for the more easily fusible and oxidizable metals, such as tin, lead,
and zinc, it is advisable to keep the gas quantities rather below the
figure given, so as to avoid any possibility of overheating and burning
any portion of the wire.
The outer jet performs a threefold purpose: it keeps the nozzles and
wire cool, it cools the object, and it produces the requisite velocity.
[Illustration: Fig. 145.--DIAGRAMMATIC REPRESENTATION OF MELTING AND
SPRAYING JETS IN ACTION.]
The velocity of the air leaving the jet will be independent of the
volume discharged, and depends only upon the pressure at the jet, so
long as there is no disturbance due to the entraining of air from
the surrounding atmosphere. This, of course, will actually occur in
practice, and the layer of air must have a certain thickness in order
to prevent its being broken up, and its velocity destroyed by mixing
with the surrounding atmosphere.
As at present constructed the standard pistol uses about 0·55 to 0·6
cubic foot per minute for every 1 lb. per square inch air pressure,
so that with an air supply at 80 lb. per square inch, which is a very
suitable figure for ordinary spraying, the air consumption will be from
45 to 50 cubic feet per minute.
The bulk of this will be from 830 to 920 grammes, and the mass of metal
sprayed by this air will be from about 8 grammes in the case of iron to
about 200 grammes in the case of lead.
The action of deposition is probably a complex one. The minute
particles of solid metal are driven with such force against the object
that, in some cases, they fuse, but owing to their small relative
size, are promptly chilled by the object to which they adhere. If any
of the particles are molten or gaseous they will adhere. In addition,
the suddenly chilled particles are possibly, or even probably, in the
state of unstable equilibrium found in "Prince Rupert's Drops," and act
like so many minute bombs, bursting on impact into almost molecular
dimensions, and penetrating the smallest cracks and fissures of the
object.
The process requires some care in manipulation, as, by varying the
conditions, it is possible to spray porous or non-porous coatings,
and, with some metals, anything from a pure metal to a pure oxide.
With care, however, non-porous, oxide-free, adherent coatings can be
produced, of almost any metal on almost any solid.
In addition to metals, it is possible to spray fusible non-metals,
or, by stranded wires, alloys of metals or mixture of metals with
non-metals.
The process is so new that its uses are still partly to be developed.
But it is easy to see that it may have far-reaching value for
protective coatings against weather or fire, for ornament, for
electrical resistance and conductors, for the production of special
alloys, for joint making, and for many other purposes.
Quite in a different category comes that of very fine casting. The
surface of a pattern, polished or slightly greasy, is most minutely
copied, and it is possible to produce process blocks very rapidly. It
may be useful to line moulds before pouring in a metal. The application
of the process to the production of very fine or coarse metallic
powders is being investigated.
The bulk of the work has hitherto been carried on in laboratories,
but the apparatus is gradually becoming used in the more progressive
factories, where extended facilities, and the knowledge of specialised
requirements, will ensure a rapid improvement in technique and results.
[Illustration: Fig. 146.--AN EXAMPLE OF SPRAYED DECORATIVE WORK.
(AEROGRAPH.)]
[Illustration: Fig. 147.--SHADED WORK BY THE AEROGRAPH.]
The research on the lower melting point metals has been greater than on
the others, and undoubtedly the economy with them both can be greatly
improved. Preheating of gases and air, supplementary flames acting
in front of the main jet, and electrical methods of heating, are all
still the subject of experiment.
The following metals are among those which have been successfully
sprayed by this process:--Aluminium, brass, bronze, copper,
cupro-nickel, iron, gold, nickel, silver, tin, zinc, lead.
It will be obvious that this method is a most useful one to employ
when it is desired to prevent iron from rusting on machine parts which
cannot possibly be treated by chemical or other anti-rust processes,
and be rendered immune from rusting by treatment where they stand. To
give some idea of the cost, it may be said that if the thickness of
0.001 of one inch of zinc is deposited, the cost of metal for coating
10 square feet would only be a fraction over 4d.; while for lead the
cost would be about 2d. The amount of gas used is not a large item,
being at the rate per minute of 0.50 cubic foot of oxygen and 0.55
cubic foot of coal gas when spraying zinc, and 0.101 cubic foot less
in each case where lead is being used in the pistol. These figures are
given on the authority of the "Daily Telegraph."
[Illustration: Fig. 148.--SHOW CARD.]
[Illustration: Fig. 149.--A SPRAYED FRIEZE (AEROGRAPH).]
INDEX
PAGE
Accessories 121-133
Advantages of Dipping 22
Advantages of Dipping Piano Cases 46
Aerograph 81
Aerograph Air Pump and Tank Combined 118
Aerograph Electric Motor Outfit 83
Aerograph Spraying Cabinet 127
Aerograph Turntable 134
Aeron 85-87
Agitating Apparatus 9-15
Agricultural Implements, Dipping 58
Air Drying Enamels 180
Air-drying coloured Japans 157
Air Heater 137
Air Pump and Tank Combined 118
Air Pump for Large Installation 119
Air Transformer Set 93
Airostyle 97
Airostyle Air Compressor 115
Airostyle Central Draught Fan 125
Airostyle Plant 121
Airostyle Plants for 16 Operators on Small Work 155
Airostyle Plant Showing Ventilator 199
Alabastine 29
Apparatus for Dipping Piano Cases 42
Application of Stoving Enamels 179
Artistic Application of Paint Spraying 201
Artists' Type of Invincible Sprayer 107
Asbestine 73
Auto Electric Air Heater 137, 139
Auto Filter 93
Automatic Control of Drying Room 68
Automatic Electric Controller 111
Automatic Finishing of Pianos 42
Automobiles, Latest Method of Finishing 216
Baird Machine Co. 249
Baking Enamel 63
Baking Heats, Safe for Pigment Colours 187
Baking or Stoving, Hints on 180
Barytes, Precipitated 70
Baskets, Fancy 147
Bean Spray Pump Co. 247
Bearings, Paint Proof 13
Bedsteads 33
Bedsteads, Dipping 58
Bedsteads, White Work 184
Berkel and Parnall's Slicing Machine Co., Ltd. 167
Bin for Spraying Light Articles 148
Birmingham Small Arms Co. 147-164
Black Japan Finishes 183
Blinds for Paint Dipping Tank 10
Block and Tackle 93
Blooming of Varnish 68
Blues 205
Bone Black 70
Bookbinding 146
Brown, E. C. & Co. 246
Brown Sprayer with Extension Rod, The 246
Browns 207
Bronzing 194
Brush Graining 208
Brushing versus Spraying 193
Burnt Sienna 70
Cabinets 127
Cadby, G. & Sons 164
Cans, Painting by Dipping 7
Carriage Department, Woolwich Arsenal 54
Carriages 146
Carriers for Dipping Piano Cases 42
Casements 7, 37
Casements Dipping 60, 61, 65
Casements, Steel 60
Celluloid Buttons 3
Celluloid Varnish, Recipe for 150
Central Draught Fan 125
Chicago White Lead and Oil Co. 188
China Clay 73
China Fruit Dish Decorated with the Airostyle 217
Cleaning Metal Parts 41
Coach Body Painting 55
Coal Box, Metal Decoration done by Airostyle 241
Coats of Paint, number 21
Collapsible Gates 33
Colour Glazing 202
Colour on Bedsteads 33
Colour Specimens, Spraying 153
Colour Varnishes, Transparent 184
Coloured Enamels 59
Compressed Air, Painting by 78
Compressed Air, Supply of 113
Compressor for Airostyle Plant 165
Concentric Form of Spray 79
Construction of Airostyle 98
Cost of Paint Dipping Plant 2
Cover for Tank 11
Crabs 18
Crane Eureka 103
Crane Record 104
Crittall Manufacturing Co. 60
Cycle Frames 197
Cycle Parts 146
Davis Gas Stove Co., Ltd. 161, 165
Decorative Work, an Example of Sprayed 261
Deed Boxes 38
Demar Varnish 75
Designs for Lamp Shades Done by Spraying 203
De Vilbiss Air Compressor 115
De Vilbiss Auto Cool Fan 125
De Vilbiss Fumexer or Spraying Cabinet 131
De Vilbiss Manufacturing Co. 85
Diogrammatic Representation of Melting and Spraying
Jets in Action 259
Different Trades in Spraying, Requirements of 33, 141
Dipping and Spraying Compared 197
Dipping and Spraying Paints Compared 188
Dipping Casements 61, 65
Dipping Paints 7, 70, 72
Dipping Process, Advantages of 22
Dipping, Quantity of Paint Required for 77
Dipping Sewing Machine Parts 34
Dipping Tanks 57
Dipping Troughs 238
Dripping Platform 9
Driving Gear for Tank 14
Drying Room, Model 67
Durability of Dipping Paints 1
Dust, Excluding 64
Electric Controller 111
Electric Hoist for Heavy Goods 27
Electric Motor Outfit 83
Electrical Work 147
Elevation of Spraying Plant 199
Enamel, Stoving 63
Enamelling, Slate 152
Enamels 179
Enamels, Air Drying 180
Enamels for Steel Furniture 183
Enamels, Heat Resisting and Slow Drying 180
Enamels, Stoving 178
Eureka Spraying Machine 103
Evaporation of Turpentine 77
Evolution of Spraying Apparatus 78
Exhaust 113
Exhaust Installation 122
Fan, Central Draught 104, 124
Fancy Baskets 147
Files 38
Filler for Iron 26
Filler, Harland's 29
Finishing of Pianos 42, 43
Finishing Room 53
Flash Point of Turpentine 76
Fletcher, Russell & Co., Ltd. 167
Floco Process 223
Flowing-on System 25, 216
Ford Motor Co., Ltd. 54, 59, 216
Four Oaks Spraying Machine Co. 247
Freight Car, Painting 250
Frieze, a Sprayed 267
Furniture, Metal 38
Fumexer 86, 129, 135
Gas Fires 197
Gas Meter Co., Ltd. 172
Gas Meters, Masks for 142
Gas Meters, Spraying 148, 171
Gas Light and Coke Co. 171, 181, 185, 191
Gas Stoves and Ranges 149
Gasometer, Painting 83
Gates, Collapsible 33
Gear Box, Paint Proof 13
Gibbons, James 58
Gittings, Hills and Boothby, Ltd. 168
Glazing Colours 202, 205
Gloss Paint 71
Goodyear Stove, a Typical 237
Golden Ochre 70
Graining and Scumbling 208
Graining Grounds 212
Grays 207
Greens 207
Hanger, Iron 34, 38
Hanging Apparatus 16
Hard Wood, Primers for 74
Hard Wood, White Dip for 75
Harland, Wm. & Sons 29
Harrison, McGregor & Co. 58
Hart Patent Mask 143
Hayward Bros. & Eckstein, Ltd. 60
Heat of Drying Room 69
Heat Resisting and Slow Drying Enamels 180
Heavy Goods, Hoist for 27
Henley's Telegraph Works, Ltd. 147
Hickory Wheels 54
Hints on Stoving or Baking 180
Hoist for Heavy Goods 27
Hoists 18
Holden, Arthur & Co, Ltd. 167
Holes in Woodwork, Stopping 29
Hook for Suspending 17, 64
Hot Air Method 235
Illingworth on White Spirit 76
Imitating Marbles 210
Imitation Wood Effects 183
Immersing Mangle Frames 35
Immersion, Painting by 7, 11
Implement Manufacturers 14
Indian Red 70
Introduction 1
Invincible Sprayer 105
Iron, Filler for 26
Iron Hanger 38
Iron Rods 34
Iron Sashes 7
Iron Window Frames 37
Italian Raw Sienna 70
Joist and Wheels Supplying Hanger 16
Kerosene Oil 75
Kettle Type of Spray 78
Khaki Paint 57
Kingsbury Manufacturing Co, Ltd. 168
Lacquers for Spraying 80
Lacquers, Paints, etc, for Spraying 177
Lamp Shades, Designs done by Spraying 203
Lime and Whitewash Sprayers 241
Limewashing by Machine with 8ft. Bamboo Pole 245
Limewhite Sprayer, Merryweathers 247
Location of Work Cabinets 127
Lockers 38
Lowering Piano Cases into the Varnish Tank 47
Lucas, John & Co. 188
Lucas, Joseph, Ltd. 160, 169, 173, 175, 181
Machine for Metal Spraying 256
Making Stencils 144
Mander Brothers 154
Mangle Frames Immersing 35
Marble Grounds 210
Marshall Sons & Co, Ltd. 59
Mask Hart Patent 143
Masks and Stencils 141
Masks for Gas Meters 142
Masury, John W. & Son 189
McLennan System 9
Melting and Spraying Jets in Action 259
Merryweather Limewhite Sprayer 247
Metal Decoration 241
Metal Furniture 38
Metal Goods 38
Metal Motor Parts 41
Metal, Primers for 74
Metal Sheets, Dipping 58
Metal Sprayer, Details of 257
Metal Spraying 255
Metal Spraying Machine 256
Metal, White Dipping for 75
Midland Sprayer 108
Model Drying Room 67
Moller and Schumann Co. 180
Morris, Herbert, Limited 21
Morris Standard Electric Trolley Hoist 23
Motor Bodies, The Floco System of Painting 224
Motor Car Shops 231
Motor Outfit for Spraying 83
Motor Parts, Metal 41
Motor Wheels 54
Objections sometimes urged against Spraying 194
Ochre 70
Office Partitions 60
Oil and Water Separator 111
Oil in Dipping Paints 72
Oxford Ochre 70
Oven Baking Methods 232
Overhead Rails 57
Paasche Air Brush 109
Paasche Automatic Electric Controller 111
Paasche Motor Driven Fan 124
Paasche Turn-Table 135
Paint Dipping 7
Paint Dipping Plant, Cost of 2
Paint Dipping, Simple Form of 7
Paint Dipping Tank 10
Paint for Casements 37
Paint for Metal Work 41
Paint for Wagons 57
Paint, Number of Coats 21
Paint Proof Bearings 13
Paint Sprayer, Portable 250
Paint Spraying Apparatus Used by the Pennsylvania Railroad 252
Paint Spraying, Artistic Application of 201
Paint, Supply of 113, 122
Paint Tank 8
Painting a Freight Car 250
Painting by Compressed Air 78
Painting by Immersion 7, 11
Painting Gasometer 83
Painting Motor Bodies the Floco System of 224
Painting Motor Wheels 54
Paints Durability of 1
Paint for Dipping 70
Paints, Spreading Capacity of 77
Part End Elevation of Plant for 12 Operators 159
Pennsylvania Railroad Company 250
Perkins System of Heating 235
Phillips & Son 58
Philorite 30
Piano Cases, Lowering into the Varnish Tank 47
Pianos, Finishing of 39
Pickling Metal Parts 41
Picture Frames 149
Picture Mouldings 149
Piece Work 145
Pigment Colours, Safe Baking Heats for 187
Pinchin Johnson's Drying Room 68
Plants, Some Typical 54, 158
Platform, Dipping 9
Portable Paint Sprayer for Railing and other Work 250
Precipitated Barytes 70
Preparing Wood Before Painting 25
Pressure in Spraying 80
Primers and Surfacers 235
Primers for Metal 71
Primers for Soft Wood 74
Protecting Parts not to be Painted 24
Prussian Blue 70
Purifying Air 114
Quantity of Paint Required for Dipping 77
Raido process 232
Rails and Hanging Apparatus 16
Rails for Overhead 57
Railway Work, Portable Paint Sprayer for 250
Raw Sienna 70
Recipe for Celluloid Varnish 150
Record Pistol 97, 99
Reds 205
Reducing Varnish 87
Requirements of Special Trades 33, 141, 145
Rims and Wheels 41
Rods, Iron 34
Rubbing Down 30
Safe Baking Heats of Pigment Colours 187
Scrubbing Air 114
Scumbling and Colour Glazing 202
Scumbling and Graining 208
Second Coat Dipping Paints 74
Sectional Drawing of Metal Spraying Machine 258
Sewing Machine Parts, Dipping 34
Shaded Effects produced by Spraying 213
Shaded Work by the Aerograph 263
Shafting for Tank 14
Sheets Metal Dipping 38, 58
Shellac Spraying 87
Ships' Hulls Spraying 151
Spraying Plant, Elevation of 199
Spraying, Quantity of Paint Required 77
Spraying Requirement of Different Trades 121
Spraying Ships' Hulls 151
Spraying versus Brushing 193
Staircases 7
Standard Hydraulic Immersion System 42
Standard Varnish Co 42
Steel Casements 60
Steel Furniture Enamels 183
Steel Implements 197
Steel Office Partitions 60
Steel Plate Fan 125
Steel Sheets 1, 12
Steel Wheels 41
Steel Wool for Rubbing Down 30
Stencils and Masks 141
Stencils, Making 144
Stirrers and Blinds for Paint Dipping Tank 10
Stopping Holes in Woodwork 29
Stove, a Typical Goodyear 237
Stoving Blacks 179
Show Card Done by Spraying 69, 209, 225, 239
Shop Fronts 60
Side Elevation of Plant for 12 Operators 158
Skylights 60
Slate Enamelling 152
Sliding Doors 60
Soft Wood, White Dip for 75
Soft Woods, Primers for 74
Spray, Concentric Form of 79
Sprayed Decorative Work, An Example 261
Spraying and Dipping Compared 197
Spraying and Dipping Paints Compared 188
Spraying Apparatus for Painting Freight Cars 252
Spraying Apparatus, Types of 81
Spraying Cabinets 127
Spreading Capacity of Paints 77
Spraying Colour Specimens 153
Spraying Metal 255
Spraying, Objections Sometimes Urged Against 194
Spraying Plant, Cost of 2
Stoving Enamel 63, 178
Stoving or Baking, Hints on 180
Stoving Temperatures 187
Stoves, Notes on the Construction of 235
Sub Frame for Tank 14
Supply of Compressed Air 113
Supply of Paint 122
Suspending Hook 64
Table Cover Decorated with the Airostyle 219
Tank and Air Pump Combined 118
Tanks for Dipping 57
Tank for Dipping Metal Windows 63
Tank for Painting Steel Sheets 12
Tank Paint 8
Tank, Special Form of 9
Tank Used in Flowing on Paint 222
Tapered Cans 7
Temperatures for Stoving 187
Test for White Spirit 76
Three Tank Plant 15
Thornley and Knight, Ltd. 157
Time Saving 1
Toys 1
Trade, Requirements of Different 33
Tramcars 154
Transparent Colour Varnishes 184
Trolley Hoist 19
Troughs 41
Tumbling Barrel Process 248, 249
Turkey Umber 70
Turn-Tables 129, 130, 134
Turpentine, Flash Point of 76
Type G Aeron 68
Types of Spraying Apparatus 81
Typical Hoist 19
Typical Plants, Some 54, 158
Ultra Airostyle 101
Umber 70
Varnish, Quantity Required for Piano Cases 46
Varnishes for Spraying 80, 177
Varnishes, Transparent Colour 184
Venetian Red 70
Ventilation of Paint Shop 67
Ventilator for Plant 123
Volume of Air in Spraying 80
Wagons, Painting 54
Wagons, Store Room 61
Wells, A. C. & Co. 244
Wheels, Rims of 41
White Dipping for Meta 75
White Paint for Dipping 71
White Paste Primer 75
"White Paints and Painting Materials" 72
White Spirit 76
White Work Bedsteads, etc. 33, 184
Whitewash Sprayers 241
Whitewashing Machines 78
Whiting 73
Wilkinson, Heywood and Clark 11
Willys-Overland Automobile Factory 228
Winch 18
Window Frames, Iron 37
Wood Effects, Imitation 183
Woodwork Preparing before Painting 25
Woodwork, Stopping Holes in 29
Woolwich Arsenal, Carriage Department 54
Woolwich Arsenal Store Room 61
Work Cabinets 127
Yellows 206
Zinc Oxide 73
Zinc Stencils 145
_ADVERTISEMENTS._
STANDARD VARNISH WORKS.
[Illustration]
Consulting Specialists respecting, and Manufacturers of every class of
Varnish for all Industrial purposes INSULATING VARNISHES, CARRIAGE,
AUTOMOBILE, MARINE & DECORATORS' VARNISHES, etc.
Patentees of the new STANDARD HYDRAULIC IMMERSION SYSTEM described on
pages 42-53 of this publication.
Correspondence invited from responsible houses:
NEW YORK ELM PARK, STATEN ISLAND.
CHICAGO 2,600 FEDERAL STREET.
TORONTO INTERNATIONAL VARNISH Co., Ltd.
BRUSSELS 26, RUE GAUCHERET.
PARIS 34, RUE DE CHABROL.
MELBOURNE 479, COLLINS STREET.
LONDON 27, BEVIS MARKS, E.C.
THE AIROSTYLE
THE ONE COMPLETE & EFFICIENT SYSTEM OF COMPRESSED AIR PAINTING,
JAPANNING, VARNISHING, Etc.
Manufactured throughout by
The AIROSTYLE & LITHOS, Ltd.,
35, St. Bride Street, Ludgate Circus,
TELE PHONE: 12025 CENTRAL.
GRAMS: STAINLESS, LONDON. London, E.C.
THE
AIROSTYLE
COMPRESSED AIR
PAINTING PLANTS
ARE IN DAILY USE
at the Leading Works for
Motor Cars, Side Cars, etc.
Gas Meters
Gas Fires, Radiators, etc.
Kitchen Ranges, Grates, etc.
Cycles and Motor Cycles
Cycle and Motor Accessories
Carriage Lamps
Leather Manufactures
Buttons
Toys
Baby Carriages
Sewing Machines
China and Glass
Electrical Apparatus
Scientific Instruments
Constructional Work
Horticultural Buildings, etc.
Tinplate Work
Munitions
General Japanned Goods
Porcelain Enamelled Goods
Advertising Signs
Textile Productions
Rubber Goods
Typewriters
Tiles
etc., etc., etc., etc.
Manufactured throughout by
The AIROSTYLE & LITHOS, Ltd.,
35, St. Bride Street, Ludgate Circus,
TELE PHONE: 12025 CENTRAL. London, E.C.
GRAMS: STAINLESS, LONDON.
PECORA
FIRST COATERS, FINISHING COATS & THINNERS FOR USE BY THE IMMERSION
(DIPPING) PROCESS OR APPLICATION BY COMPRESSED AIR (SPRAY) ARE THE
RESULT OF
1st.--Theoretical Combinations of pigments
and vehicles.
2nd.--Careful _practical_ test of these combinations
and changes to meet given
requirements.
3rd.--Close study of the finished article to
determine durability.
4th.--Twenty-five years experience in the
production of special finishes, which
must meet unusually severe conditions.
Our Experimental Laboratory is equipped with a complete dipping,
spraying and baking plant, and is at the service of any interested
person.
We would be glad to finish samples of your product along any desired
lines, or to follow out our own ideas as to the most desirable method.
PECORA PAINT COMPANY.
4th & Erie Ave. Philadelphia, Pa., U.S.A.
Est. 1862 by Smith Bowen. Incorporated 1911.
ARE YOU USING
"AEROGRAPH" SPRAYS
[Illustration]
_FOR_
Plain Painting, Decorating, Japanning, Enamelling, Varnishing and
Lacquering. Also for Distempers of all kinds. Five times Faster than
any other Method.
Stationary and Portable Painting Outfits
_PERFECT CONTROL. SUPERIOR RESULTS._
THE AEROGRAPH CO., LTD.
43, HOLBORN VIADUCT, LONDON, E.C.
BRITISH AND FOREIGN GOVERNMENT CONTRACTORS.
[Illustration]
_CRANE'S SPRAYERS_
[Illustration]
For ENAMELS, PAINTS, LACQUERS, VARNISHES, ETC., ARE
--THE GREATEST ECONOMISERS OF TIME-- MATERIAL & LABOUR EXTANT--The
Handiest and most Efficient yet Devised and further
[Illustration]
They ENSURE the Best Results.
Write for details:
FREDK. CRANE CHEMICAL Co.,
Bordesley Green, B'HAM.
[Illustration]
W. GOODYEAR & Sons,
[Illustration] Manufacturers, DUDLEY. [Illustration]
SPECIALISTS IN:
_Enamelling Stoves_
_for_
[Illustration] _All Purposes_ [Illustration]
WRITE FOR CATALOGUE.
[Illustration: ESTABLISHED ·1760·]
If you will come to Homerton to see a practical demonstration of the
finishing of your own products by the economical Spraying process,
our facilities are at your service without charge or obligation.
Those facilities are: a fully equipped spraying plant--probably the
first spraying expert in the Kingdom--and a range of spray paints
covering the entire process from Filler to Varnish coat, perfected by
experience. We specialise too in paints for Dipping and shall be glad
to demonstrate to you the economy of either or both.
Berger's Spray Paints & Dipping Paints.
Lewis Berger & Sons, Ltd.
Makers of Paints, Colours & Varnishes,
HOMERTON, LONDON, N.E.
Branches--Paris, Copenhagen, Sydney, Wellington, Bombay, New York.
[Illustration]
PNEUMATIC SPRAYING
OF PAINTS, ENAMELS, LACQUERS, VARNISHES, RUBBER SOLUTION, &c.
If you use any of the above in quantities you cannot afford to be
without a
PNEUMATIC SPRAYING PLANT.
[Illustration]
BETTER FINISH, SMALLER BILLS for material, much cheaper production.
The Midland Pneumatic Spraying Plant is the product of practical
Engineers and is ALL BRITISH.
LET US DEMONSTRATE ITS POSSIBILITIES AND ADVISE YOU.
Wire--Blast, Birmingham; 'Phone--Central 5463; or write--
The MIDLAND FAN Co., Ltd., 46, Aston Road, BIRMINGHAM.
[Illustration: GITTINGS, HILLS & BOOTHBY, L^D. BIRMINGHAM.]
SPECIALISTS FOR
SPRAYING, DIPPING & STOVING VARNISHES & PAINTS.
G. H. & B., Ltd., will be pleased to show their Spraying
Installation to any firm desirous of seeing
and testing same--customers' own material
sprayed.
DIPPING TANKS loaned to customers to enable adequate
tests to be made.
DO YOU WANT TO
SAVE MONEY ?
Then take up the most economical methods of painting, viz.,
DIPPING AND SPRAYING.
Gittings, Hills & Boothby, Ltd.,
Varnish and Paint Manufacturers,
LONG ACRE,
BIRMINGHAM.
And at
82, TURNMILL STREET,
LONDON. E. C.
_One Man with the Aeron is worth 2 to 10 without_
There is not only this 50 to 90% saving in time and labour, because of
the speed that is possible with the AERON SYSTEM of spraying, but there
is also produced a better quality of finish than is obtainable with any
other method. The surface is absolutely uniform, smooth and even of
thickness. It is free from all sags, runs, thin spots or fatty edges.
[Illustration]
The AERON SYSTEM is simple and easy to operate. Ordinarily inaccessible
places, and carved and irregular surfaces, are quickly and uniformly
finished.
The AERON SYSTEM installed in your finishing room will produce the
utmost in results at the lowest possible cost.
Address:
The DeVilbiss Manufacturing Co.
71 Newman St.,
Oxford St., London, W., Eng.: Toledo, Ohio, U.S.A.
Finish Your Products, Large or Small, Wood or Metal, with the
[Illustration: Guaranteed _Aeron System_ Paints With Air]
The AERON SYSTEM of applying varnishes, enamels, shellacs, lacquers,
japans, bronzes, and practically every kind of finishing material, on
wood and metal products with compressed air, is the result of extensive
painting and mechanical experience, and a comprehensive study of
finishing problems.
The AERON SYSTEM is complete in every detail. Every angle and problem
of the application of finishing materials is successfully met with a
thoroughness and positiveness--with a certainty of greater quality,
speed, economy and efficiency--by this SYSTEM. There is a wide variety
of "best type" Aerons and Accessory Equipment, meeting all requirements
and enabling the operator to obtain striking results.
Let us send you full and interesting particulars, --and a booklet of
equipment facts.--
Address:
The DeVilbiss Manufacturing Co.
71 Newman St.,
Oxford St., London, W., Eng.: Toledo, Ohio, U.S.A.
Telegrams--Varnish, Birmingham.
ARTHUR HOLDEN & SONS, Ld.
(Established nearly a Century)
Bradford Street, BIRMINGHAM.
Specialists in Spraying Finishes for every Trade.
Spraying Paints, Enamels, Japans, Varnishes, Varnish Paints, etc.,
FOR STOVING OR SELF-DRYING IN ALL COLOURS AND QUALITIES.
TRADES ALREADY SUPPLIED:--
Photographic, Optical, Electrical & Surgical Apparatus Manufacturers.
Bicycles, Motor Bodies, Motor and Cycle accessories. Steel Toys, Wood
Toys, Lamps, Iron Fittings. Mail Carts, Radiators, Trunks, Weighing
Machines, Scales, etc., etc.
The DeVilbiss Aeron
[Illustration]
The most Efficient and Flexible
:: Spraying Machine. ::
Sold by
LLEWELLYN RYLAND, LTD.,
BIRMINGHAM.
Manufacturers of
LACQUERS, PAINTS, JAPANS AND VARNISHES,
Suitable for Spraying.
Wells' "Lightning" Lime & Colour Washer.
A Great SAVING of TIME, LABOUR AND MONEY.
NO OUTSIDE POWER REQUIRED. OVER 5,000 SOLD.
SAVES its Cost in a Few Days
LIME, WHITING, or COLD WATER PAINTS
applied at a speed of from 10 to 20 square
yards per minute, in a manner superior to
brushwork. One coat with the machine on
rough surfaces is equal to two applied with
brushes.
ENLARGED PATTERNS.
REDUCED PRICES.
No. 6a--Small Size, fed from
pail, 5 gallons £5 5 0
" 4--8 gallons £8 5 0
" 4a On Wheels, same capacity £9 0 0
" 5a--On Wheels, 12 gallons £11 5 0
A. C. WELLS & CO., MIDLAND ROAD, ST. PANCRAS, LONDON.
Works--Carnarvon Street, MANCHESTER.
[Illustration: Nos. 4a and 5a Patterns.]
THE
PERKINS CLOSED SYSTEM
OF
HEATING BY HOT WATER
FOR
ENAMELLING, JAPANNING, DRYING, etc.
_Schemes & Estimates Submitted Free of Charge._
PERKINS, ENGINEERS, LTD.,
KINGSWAY HOUSE, KINGSWAY, W.C.
_Telephone No._ _Telegraphic Address--_
_482 Gerrard._ _"Arktos" Westcent, London._
"PAINT & COLOUR MIXING."
By ARTHUR SEYMOUR JENNINGS.
5th EDITION, REVISED & ENLARGED.
A Practical Handbook for Painters, Decorators, Artists, and all who
have to mix colours.
Containing 300 samples of actual oil and water paints and water colours
of various colours, including the principal graining grounds and
upwards of 600 different colour mixtures, with instructions on colour
and paint mixing generally, testing colours, &c., &c.
With fourteen coloured plates.
Contents.--Paints and Colour Mixing, Colours or Stainers, How to
learn to mix and match colours, Reds and how to mix them, Blues and
how to mix them, Yellows and how to mix them, Greens and how to mix
them, Browns and how to mix them, Greys and Greys, White and Blacks,
Black Japan in colour mixing, Glazing, Graining grounds and Graining
colours, Mixing paints and colours on the manufacturing scale, Water
paints, Distempers, Artists' water colours and how to mix them, testing
colours, notes on harmony, The proportions of materials, Notes, &c.
POST FREE 5/4.
E. & F. N. SPON, Ltd.,
57, Haymarket, S.W.
THE PAINTERS' POCKET BOOK.
By ARTHUR SEYMOUR JENNINGS.
Many thousands of copies of this exceedingly useful book have been sold.
3s. 3d. Post Free.
_SYNOPSIS OF CONTENTS._
Simple methods for Painters' materials.
Behaviour of different pigments.
How to measure Painters' work.
Painters' Prices for all kinds of Paint work, Sign
Writing, Varnishing, Gilding, Enamelling,
Marbling, Graining, Paperhanging, etc., etc.
Many Miniature Stencils which can be submitted
to clients for their selection and afterwards
be increased in size.
Ribbons for Church Decoration.
Defects in Painting and how to remedy them.
Colours and how to mix them.
Hints on Practical Geometry and setting out of
work.
Symbols and Emblems in Church Decoration,
on Flags, in Heraldry, etc.
Poisoning and remedies.
Concise Dictionary of terms used in Painting,
Building, Architecture, Art, Applied Chemistry,
etc., etc., with many illustrations.
Hints on Paperhanging.
Tables for Wallpapers, English, French, and
American.
Table for ceiling papers.
Table of superficial yards.
Table of materials required according to the
surface to be painted.
Roman Numerals.
Table for calculating the price of Linseed Oil
and Turpentine.
Wages Table.
The Orders, Greek and Roman.
Table of Prices.
Table of discounts and percentages.
Colours and Pigments, permanent and otherwise.
Linseed Oil--percentage required for grinding
dry Pigments.
How oils are sold.
How far paints will spread.
Mensuration.
English and American gallons.
Specific gravity.
Table of Thermometrical degrees.
Superficial contents of squares of glass.
Ready reckoner.
Notes of Insurance.
Table of Pigments, etc., etc.
THE TRADE PAPERS PUBLISHING CO., LTD.,
365, Birkbeck Bank Chambers,
HIGH HOLBORN, W.C.
PRACTICAL BOOKS FOR PAINTERS.
Post Free.
PAINT AND COLOUR MIXING. A Practical
Handbook for Painters, Decorators, Artists, and all
who have to mix colours. Containing 300 samples
of actual oil and water colours. By Arthur Seymour
Jennings 5/4
HOUSE PAINTING AND DECORATION. A
popular guide, by Arthur Seymour Jennings 2/3
PRACTICAL CHURCH DECORATION. A guide
to the Design and Execution of Decoration of
Churches, Chapels and Ecclesiastical Structures.
By Arthur Louis Duthie 3/3
SCUMBLING AND COLOUR GLAZING, illustrated
with 48 examples of glazed work. By Andrew Millar 3/3
ZINC OXIDE AND ITS USES. By J. Cruickshank
Smith 2/3
PRACTICAL GILDING, BRONZING, LACQUERING
AND GLASS EMBOSSING. Illustrated
by actual examples of Gilded and Lacquered Relief
and other Decorations. By F. Scott-Mitchell 3/3
THE PAINTERS' AND BUILDERS' POCKET
BOOK. By Arthur Seymour Jennings. Consists of
252 pages, containing a large amount of information
of the greatest use to Painters and Builders 3/3
DECORATORS' SYMBOLS, EMBLEMS AND
DEVICES. By G. C. Rothery 3/3
GRAINING AND MARBLING, THE PRACTICAL
ARTS OF. By James Petrie. Each plate measures
17-1/2 × 11-1/2 and gives the different stages of the work.
Published in 14 parts at 2/6 each, or bound volume
25/-
Office of "THE DECORATOR,"
365, Birkbeck Bank Chambers,
High Holborn, London, W.C.
PRACTICAL BOOKS FOR PAINTERS.
Post Free.
STENCILS AND STENCILLING. For all purposes,
Artistic and Decorative. 154 pages of designs. By
Arthur Louis Duthie 3/3
PAINT AND PAINTING DEFECTS, their Detection,
Cause and Cure. By J. Cruickshank Smith 3/3
PAINTERS' BUSINESS BOOK. A manual of up-to-date
methods of obtaining business, submitting
Estimates, Book-keeping, Buying and Testing
materials, etc., with many tables. By C. E. Oliver 3/3
CLARK'S BOOK OF ALPHABETS, two parts.
For Signwriters, Designers, Decorators, and
Draughtsmen, each 1/2
HEWETT'S DISTINCTIVE LETTERING AND
DESIGNS 1/2
KAEMMERER'S LETTER BOOK. Containing
several hundred alphabets in 140 plates, together
with descriptive text 18/6
THE ART OF SHOW CARD WRITING. By C. J.
Strong. Contains many beautiful Designs 10/-
STRONG'S BOOK OF DESIGNS. Invaluable to
the Signpainter, Show Card Writer, etc. Containing,
in addition to Posters, Show Cards, Ribbons, etc.,
33 pages of ornamental work in Colour 20/-
ATKINSON'S SIGN PAINTING, replete with original
Designs, Colour Combinations, etc. 12/7
GRAINING, ANCIENT AND MODERN. By Wm.
E. Wall 12/4
Office of "THE DECORATOR,"
365, Birkbeck Bank Chambers,
High Holborn, London, W.C.
THE OFFICIAL ORGAN OF
The London Association of Foremen Engineers.
The Leeds Association of Engineers.
The Stoke-on-Trent Engineers' Association.
Sixpence a Copy.
_THE_
_"Managing Engineer."_
Five Shillings a Year.
PUBLISHED BY
THOMAS TOFTS, 93 & 94, Chancery Lane, London, W.C.
Transcribers Notes:
Punctuation and spelling inaccuracies were silently corrected.
Archaic and variable spelling has been preserved.
Variations in hyphenation and compound words have been preserved.
Fig 125. Design for Show Card is wrongly shown to be on page 223
in the list of illustrations. This has been corrected to page 233.
In the index 'Sheets Metal Dipping 40, 58', has been altered to 38, 58.
Page 40 was a blank page and page 38 is near and in context
but maybe an inaccurate alteration.
Both middle and modern decimal points are used.
Italics are shown thus: _sloping_.
Bold type is shown thus: =shout=.
Small capitals have been capitalised.
The caret character (^) has been used to denote superscript.
End of the Project Gutenberg EBook of Painting by Immersion and by
Compressed Air, by Arthur Seymour Jennings
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