Japanning on metal, wood, and paper, is executed in much the same manner as similar works in spirit or oil varnishes, except that every coat of colour or varnish is dried by placing the object in an oven or chamber called a stove, and heated by flues to as high a temperature as can safely be employed without injuring the articles, or causing the varnish to blister or run. For ornamental works, the colours ordinarily employed by artists are used; they are ground in linseed oil or turpentine, and are afterwards brought to a proper consistence for working by mixing them with copal or anime varnish. The latter is generally used, as it dries quicker, and is less expensive than the copal varnish.
For black japanned works, the ground is first prepared with a coating of black, made by mixing drop ivory black to a proper consistence with dark coloured anime varnish, as this gives a blacker surface than would be produced by the japan alone. The object is then dried in the stove, three or four coats of japan are afterwards applied, and the work is dried in the stove between every coat. If the surface is required to be polished, as for the best works, five or six coats of japan are necessary to give sufficient body to prevent the japan being rubbed through in the polishing, which is effected as noticed briefly in page 1069.
For brown japanned works, the clear japan alone is used as the ground, or umber is mixed with the japan to give the required tint, and the work is afterwards dried in the oven in the same manner as black japan.
For coloured works, no japan is used, but they are painted with the ordinary painter's colours, ground with linseed oil or turpentine, and mixed with anime varnish; and the work is dried in the oven in the same manner as the black japan.
To protect the colours, and give brilliancy and durability to the surface, the work is afterwards varnished with copal or anime varnish made without driers. Two or three coats of varnish suffice for ordinary works, and five or six for the best works that are polished. Very pale varnish is of course required for light colours.
Ornamental devices are painted on the objects in the usual manner, after the general colour of the ground has been laid on. The colours are dried in the stove, and the work is finally varnished and polished just the same as plain colours, but more carefully.
Metal works require no other preparation than cleaning with turpentine, to free them from grease or oil, unless the latter should happen to be linseed oil, in which case the cleaning is generally dispensed with, and the articles are placed in the stove and heated until the oil is baked quite hard.
Wood that is intended to be used for the best japanned works requires to be thoroughly well dried before it is made up, or otherwise it would be subject to all the evils of shrinking, warping, and splitting when exposed to the heat of the stove. To avoid these evils, the wood, after having been well seasoned in the usual manner by exposure to the air, is sawn out nearly to the required forms, and baked for several days in the japanner's stove, the heat of which is gradually increased, and the wood is afterwards worked up into chairs, tables, trays, and similar articles, which are afterwards again exposed to the heat of the stove, and any cracks or other imperfections that may be thus rendered apparent are carefully stopped with putty or white lead before the japanning is commenced.
Common works in wood, said to be japanned, are, however, not stoved, but only painted, either in varnish or with common oil paint, and afterwards varnished with either anime or turpentine varnish according to quality. In the same manner iron work for common purposes is frequently coated with black paint, brunswick black, or black japan, applied without heat, and either varnished or not, according to circumstances, but all these expedients are greatly inferior to japanning.
In lackering brass and similar metals, the work requires to be perfectly cleaned from all grease or oil, the presence of which would prevent the adhesion of the lacker, and usually the metal is heated nearly to the temperature of boiling water, that the spirit may be rapidly evaporated from the lacker, in order to prevent any risk of its being chilled by the moisture of the atmosphere being condensed on the cold metal. The heat also causes the lacker to attach itself more firmly to the metal, and from the readiness with which it flows, the lacker appears much more brilliant. The heating of the metal is, however, not imperative, as metal may be lackered in the same manner that spirit varnish is applied to wood, but a dry and warm atmosphere are then essential, or the lackering may be carried on in bright sunshine, but there is greater liability of the adhesion of dust, owing to the lacker drying less rapidly, and on the whole the process is not so successful as when heat is applied.
The lackering of the metals should follow immediately after the polishing processes, which have been already explained at page 1038, or if the lackering must necessarily be delayed, the work should be thoroughly coated with clean oil, or immersed in very pure water, in order to retard the tarnishing, but which will nevertheless occur in water after the lapse of a few hours; with oil the polish is preserved much longer. Works having orna-mented surfaces from which the oil could not be readily cleaned, are sometimes closely wrapped in cloths in order to exclude the air as much as possible, but the sooner brass is lackered after polishing the more brilliant it will appear.
The works polished with oil are carefully wiped before they are heated, first with moslings, and afterwards with whitening, applied either with a rag or a brush, so as thoroughly to remove all traces of grease; those polished with water merely require to be wiped with a clean cloth, and those finished by the dipping processes are generally dried in saw-dust.