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.
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.
Fig. 93.—The Hart Patent Mask.