Finishing is critical to the success of any pin or emblem. It is important to choose the correct finish to achieve the desired effect. In jewelry manufacture, this generally is achieved using an electroplating process and is supplemented with additional techniques such as sandblasting or oxidation.
Plating utilizes a chemical bath and electric current to deposit metal onto the base metal piece. Recent technology has resulted in better efficiency and less waste contamination than in years past, but the actual process of turning a base metal part into an attractive “jewelry” product remains more of an art than a science. There are many different plating processes, but for our purpose, we will briefly discuss gold, silver, and antique or oxide plating.
Two very important considerations in the plating process is pre-preparation and cleaning. Pre-preparation consists of the various techniques for removal of extraneous metal and general smoothing of the surface. All surfaces have some high and low areas which although not readily visible, become magnified in the plating process. To smooth out these high and low areas, the pieces can be either “tubbed” or polished.
Tubbing is a process where the pieces are placed in a large cylindrical tub with a composite media. Depending on the amount of smoothing required, various levels of “coarseness” can be utilized. The tubbing machine vibrates rapidlyausing the media and jewelry pieces to rub together. Over time (usually several hours), the pieces become smooth.