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Nickel Baths

Iron and steel must be prepared by immersing in a hot solution of caustic soda or potash, thoroughly brushed, rinsed in water and dipped in a pickle of 1 part sulphuric acid, 2 part hydrochloric acid and 10 parts of water, again rinsed, thoroughly rubbed with fine well washed pumice stone or Vienna lime, again rinsed and put in the bath. If finely polished tools, they may be brushed with whiting or tripoli instead of pumice stone. Copper wire should be tightly wound around all metal articles. Small articles may be suspended from copper hooks. The battery of dynamo is placed in action before immersing the articles, which remain in the bath until they have acquired a white appearance, which will be in from five to thirty minutes, depending on the strength of the current and the size of the article. In case the article assumes a gray or black color, or feels rough and gritty, the current is too strong, or if it assumes a yellowish white appearance, it is too weak. The simplest nickel bath consists of a solution of pure double sulphate of nickel and ammonium 8 to 10 parts by weight in 100 parts of distilled water. Boil the salt in a corresponding quantity of water, say 8 to 10 parts of nickel-salt to 100 of water, depending on the temperature. With this bath cast nickel anodes and a strong current should be used. When a pure white deposit is required on unpolished surfaces the addition of 2 oz. of pure chloride of nickel to each gallon of the above solution is recommended. On an article of iron, steel, lead or its alloys a previous slight deposit of copper from a cyanide solution is advisable. It adds scarcely anything to the cost and insures a uniform coating which is not always apparent in a deposit on a light colored metal. The article after its removal from the bath should be dipped for a few seconds in boiling water, drained and dried in warm sawdust. They may then be polished, but cannot be burnished. The luster on nickel-plated objects depends greatly on the polish given them before plaint. The composition of nickel baths depends greatly upon the metals to be operated on, which can best be determined by experiment. The anodes should be suspended by strong hooks of pure nickel wire, and the articles should be placed at a distance of from 3 3/4 to 4 3/4 inches from them. If the article is to receive a thick deposit, it should be turned in the bath from time to time, from end to end, so that those portions which were down come up. Small articles which cannot be suspended are placed in a sieve, it being preferable to use a heated bath for the purpose. Iron, steel, copper, brass and bronze are usually nickeled directly, but Brittannia ware, zinc and tin are coppered or brassed before nickeling. In case a freshly prepared bath yields a dark deposit it can generally be remedied by working the bath for two or three hours.