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.
