Fig. 28.—Dipping a Coach Body at Woolwich Arsenal.
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.