Plated Ware, articles of various kinds, consisting as a rule of a cheap metal as a base covered with one of more value, as britannia metal, nickel, copper, or brass covered with silver or gold, or iron with nickel. There are two distinct methods of plating: an older one by which the silver was either soldered or fused upon the foundation metal, and a newer one of depositing the coating from a solution of a metallic salt by electro-chemical decomposition. Attaching sheets of silver by means of solder was practised by the ancient Romans, and continued in general use till the middle of the 18th century. The process is called by the French le double or lining, and the English call it French plating to distinguish it from the method which followed it, called the English method, which consisted in fusing a plate of silver upon an ingot of copper or brass without the intervention of solder, and then rolling the ingot into a sheet, This method is also called true plating, and was introduced into France about the year 1808. In 1839 it gave employment to some 2,000 workmen, the products of whose labor amounted to about 8,000,000 francs. The metal to be plated may be either very fine copper or a brass containing a very large proportion of copper.
The nickel alloys of copper, though preferred for electro-plating, do not answer for the older process because the surface is liable to oxidation, by which the silver is prevented from adhering. An ingot of copper or brass, or a mixture of the two, is cast about an inch thick, 3 in. broad, and 18 or 20 in. long. It must be free from holes or flaws, to insure which it is cast in an iron mould with rising mouthpieces to give pressure and allow impurities to float up. The surface of the ingot is smoothed with a file, and a plate of silver is laid upon the surfaces to be plated equal to 1/30 or 1/24 of the weight of copper for each side to be covered. The plate or plates are fastened on with iron wire and the edges sealed with" a little borax. It is now placed upon burning coke in the plating furnace and watched by the workman through a small hole in the door. The proper temperature of the ingot is indicated by the silver being drawn into contact with the copper. It is then removed as quickly as possible, for the two metals are then just ready to run together and form an alloy, and in fact they do this at their surfaces of contact; the rapid cooling of the surface which follows exposure to the air arrests the process.
Being now cleaned, the ingot is reduced to a sheet of the required thickness by several rollings, between each of which the ingot must be annealed to preserve its ductility. After the last annealing the sheets are immersed in hot dilute sulphuric acid and covered with fine Calais sand. They are then ready to be formed into articles by raising with the hammer, spinning on the lathe, stamping, chasing, etc. The plated wire used for making bread baskets and other light open-work utensils is made by first fashioning silver tubes by lapping sheets around a rod, then placing the cleaned tubes upon clean copper rods and heating them in a furnace, whereby the surfaces of contact are united by the formation of a film of alloy, a burnisher being used to press them together, after which the plated rod is drawn into wire of the desired size. - The newer process of electro-plating has mostly superseded these older ones, and all housekeeping plated ware is now made by forming the articles in copper bronze, nickel, britannia, or white metal, and then depositing upon them the silver or the gold, from a solution of cyanide of the metal, after which the surfaces may be burnished and otherwise embellished.
This art is extensively practised in Europe and America. Some fine ware is made by depositing a. thick coating of silver upon nickel, which, although much cheaper, has in every respect the appearance of real plate. The general principles of electro-plating and electro-gilding (as the covering with gold is technically called) are given in the article Galvanism. The details of the operations vary with different cases, and can only be intelligibly described or well understood in the work room. Nickel plating is described in the article Nickel.