Painting by Immersion and by Compressed Air: A Practical Handbook

by Arthur Seymour Jennings

To spray one, with a superior finish, takes 30 to 45 seconds, and even where some difficulty is experienced in handling, or where it is the practice to have the firebricks in place beforehand, so necessitating the use of a mask, in no case is a greater time than 1½ to 2 minutes taken. A cycle lamp, small size, takes fully 2 minutes to brush properly. To spray the same lamp takes 10 seconds. A gas meter, 5 or 10 light size, takes 7 minutes to brush. To spray one takes 1½ minutes, allowing for the time occupied in fixing and removing the somewhat elaborate mask employed for covering the indicator glass, badges, name-plate, etc.

A motor headlight takes nearly 20 minutes to brush properly, whereas to spray one takes but 1½ minutes at the outside.

To brush a cycle frame takes 10 minutes or so (brushing is still done for coloured work).

To spray either in japan or colours takes 1 to 1½ minutes, and when it is considered that a heavier coat can be applied than is the case when brushing or dipping, it will be admitted that such a result compares favourably even with dipping.

A 2-seater motor body takes from 25 to 45 minutes to brush properly.

To spray the same body takes only 6 to 8 minutes, and when it is noted that a fraction of the rubbing down is necessary in the case of the sprayed result, as against the brushed body, it will be granted that an enormous gain is to be effected.

Where two or more colours are employed, it is difficult to make comparisons as readily, but, generally speaking, it is the practice to employ two instruments per operator where the colours are applied one immediately after the other, as is the case with many electrical parts, and in this case a gain of 4 or 6 to 1 is shown over brushed work.

In some cases it has been found an advantage to spray one coat and to brush the other, especially where some difficulty is experienced in masking, and, in such cases, the only way to arrive at the most satisfactory method is by actual test.

In other cases, such as bronzing, with a celluloid medium, it is absolutely impracticable to apply these bronzes, save with the spray, unless the old method of varnishing and afterwards dusting on the bronze is adopted; but, of course, against spraying, such an obsolete method as the latter has absolutely no chance when speed is considered.