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.
