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.
Fig. 126.—The Perkins Stove.