This section is from the "Henley's Twentieth Century Formulas Recipes Processes" encyclopedia, by Norman W. Henley and others.
The first thing to be done when a vessel is to be japanned, is to free it from all grease and oil, by rubbing it with turpentine. Should the oil, however, be linseed, it may be allowed to remain on the vessel, which must in that case be put in an oven and heated till the oil becomes quite hard.
After these preliminaries, a paint of the shade desired, ground in linseed oil, is applied. For brown, umber may be used.
When the paint has been satisfactorily applied it should be hardened by heating, and then smoothed down by rubbing with ground pumice stone applied gently by means of a piece of felt moistened with water. To be done well, this requires care and patience, and, it might be added, some experience.
The vessel is next coated with a varnish, made by the following formula:
Turpentine spirit.... 8 ounces
Oil of lavender.....: 6 ounces
Camphor........... 1 drachm
Bruised copal........ 2 ounces
Perhaps some other good varnish would give equally satisfactory results.
After this the vessel is put in an oven and heated to as high a temperature as it will bear without causing the varnish to blister or run. When the varnish has become hard, the vessel is taken out and another coat is put on, which is submitted to heat as before. This process may be repeated till the judgment of the operator tells him that it is no longer advisable. Some operators mix the coloring matter directly with the varnish; when this is done, care should be taken that the pigment is first reduced to an impalpable powder, and then thoroughly mixed with the liquid.