The method was used to impart metallic finish to small parts before the electroplating method was developed. The method is still used.
A conductive coat of silver is precipitated on the plastic part from silver nitrate solution to make the m conductive. The n the part is plated in the rotating plating barrels containing acid copper plating solution and copper anodes. After the copper is deposited the articles are polished with a steel shot in a burnishing barrel. A plating of gold, silver or nickel is deposited on them by another barrel plating operation.
The conventional hot stamping process can be used to put a gold, silver or other metallic decoration on plastics. Now high lustre metalized silver foils or roll leaf are developed for exterior use.
Here silver or copper plating is deposited by chemical reaction of water based solution on the substrate. The base coat and a top coat are usually incorporated.
Here the silver containing salts are deposited on the product through a dual nozzle gun. When copper is to be applied the silver is applied first and then the copper is applied on the silver coat. A typical system will consist of a spray booth with special bottom to recover silver, mixing vessels, demineraliser for water purification and four guns: one for water to clean the part after each processing step, one for the activator to treat surface of the part, a dual nozzle gun for silver and a dual nozzle gun for copper.