CHAPTER III.
Requirements of Different Trades.
The following are a few of the special requirements of different trades as to paint dipping. The details might be lengthened almost indefinitely.
Bedsteads.
The methods adopted for the class of work will, of course, depend upon the quality of the finish required. Cheap bedsteads may be done by dipping in one coat of black japan and stoving at 350° F. In better class work several coats may be applied either by dipping or spraying, and each may be rubbed down after stoving. If a good enamel is used this is unnecessary.
When the work is white several coats—say, at least three—are necessary, for white japans cannot be made which will cover sufficiently in one coat. White lead should not be used in this class of work for the reason that a good deal of handling of parts is necessary, while the rubbing down is sometimes done with glass paper and cause dust, both of which may give rise to lead poisoning. All of the best white japans or enamels are made on a base of zinc oxide or lithopone (zinc sulphide), or a mixture of them.
Collapsible Gates.
This work is usually done by dipping in paint which dries "flat," i.e., without gloss. The colour is, as a rule, black. In fitting and adjusting the work in order that the parts will collapse readily it is necessary to apply a lubricating oil where the rods meet. This lubricating oil is difficult to remove after the adjustment has been completed, and therefore the last coat of paint is usually put on by hand. It is suggested, however, that raw linseed oil might be used instead of lubricating oil, and that this could be wiped off as soon as possible after the adjustment. In such a case the paint could be applied by dipping, as if even a little of the raw linseed oil were not removed it would not interfere with the drying of the paint to any material extent.