Lacquer. Ornamental or useful articles of brass, such as gas-fittings and some kinds of furniture, are usually lacquered to preserve the surface from discoloration or corrosion. Iron, tinplate, and other metals and alloys are also sometimes lacquered. The lacquer used is composed essentially of shell-lac or seed-lac, or both, dissolved in spirits of wine. But its composition varies considerably. One kind consists of 2 parts of shell-lac dissolved in 20 parts by weight of alcohol, less than 1 part of turpentine being mixed with it. It is customary, however, to add small quantities of one or more gum-resins, such as sandarach, amber, and anime, to the lacquer, which is coloured with gamboge, dragon's blood, and other substances. The brass, which is first heated till the hand can just safely touch it, generally receives two coats of lacquer: but sometimes the first coat is put on when the metal is cold. In the case of dark lacquering the brass is first bronzed and coated with black lead. Coal and tobacco smoke, as well as the vapour or fumes of some chemical substances, injure lacquered surfaces.
Lacquer-ware.—The lacquer used for the celebrated lacquer-ware of Japan differs entirely from the lacquer used for brass. The body of this ware is of wood, and the lacquer or varnish with which it is coated is the juice of the lacquer-tree (Rhus vernicifera), sometimes also called the varnish-tree. This remarkable lacquer not only forms a very hard surface, but, unlike other varnishes, it stands a considerable heat without injury, so that in Japan lacquered vessels are used for hot soups and hot alcoholic drinks. There are numerous kinds of Japanese lacquer-ware, the simplest kind being perhaps that with the grain of the wood seen, for which a fine transparent lacquer is used. For black lacquer-ware the juice or varnish is darkened with galls and a salt of iron, and for red it is mixed with about 20 per cent. of cinnabar; orpiment, oxide of iron, and Prussian blue being also used as colours. In the case of gold and silver lacquer-ware the varnish is mixed with about 30 per cent. of the powder of these metals in a fine state of division, so that when the surface is polished it shows a metallic lustre. Tin is used to imitate gold, the yellow hue being given by colour in the varnish.
The lacquered surface of the best ware is prepared by a very tedious process, owing to the number of coatings it receives. For the several preliminary ones crude lacquer is used, together with a single coating of powdered biscuit earthenware and water, the surface being rubbed with a whetstone after each. Two or three more coatings of lacquer are next applied, each being rubbed with charcoal and water. For the finishing coat the best lacquer is employed, and this is polished with calcined deer-horn, finely powdered, the finger and a little oil bringing up the final gloss. The various articles made, such as boxes, vessels, trays, cabinets, &c., are decorated either by inlaying with metal, ivory, or mother-of-pearl, by speckling and gilding with gold or silver, by designs in colour, by relief paintings, or by carving. The art of lacquering is a very ancient one in Japan, and fine specimens of old work bring very high prices.