One of the industries in which paint spraying is strikingly successful is that of preparing picture frames with a "gold" finish. If properly done the result is even better than if gold leaf is used, as the spray covers completely the most elaborate and intricate ornament. Picture frames or mouldings of various shapes and sizes are obtained ready for receiving the various coats necessary to give a gold finish. Formerly the whole of the operations were done by means of brushes, but this method has been wholly superseded by spraying, which approximately does the work five times as quickly and gives a far better result.
Three separate processes are employed; the first is the application of a coat of enamel, the second a coat of bronze or "gold paint," and the third the application of a transparent lacquer. The last protects the bronze from discoloration, and the manufacturers guarantee that such mouldings will last at least 5 years without tarnishing.
The whole of the work is air dried, but to facilitate the operation the workroom is kept at a temperature of about 75°F and the drying ovens up to, say, 80° or even 85°F. The first coat of enamel is sprayed on, and in about two hours is felted down with a pad similar to that used by french polishers. This is dipped in a solvent which removes all inequalities. The actual spraying is done on a long open trough shaped bin some 3 ft. 6 in. from the floor having exhausts at the bottom and thin laths placed across it at intervals of about 18 inches. The long stretches of moulding are placed on these laths lengthwise, the laths holding them in position. The spraying is done directly on them and they are turned from side to side, and when the spraying is completed each length is lifted bodily by two boys, one at each end, on to racks in the drying room which is close by and which has a large number of open iron shelves running from end to end. These shelves are quite close together, so that a large number of lengths of moulding may be dealt with at one time. Heat at about 85°F is admitted at the bottom, and the drying apartment is open from end to end in front so that the mouldings may be readily introduced. This heat also serves to warm the room.