The electro-plating process has been used commercially for years to plate metal articles with a coating of another metal. While the process itself is well understood and controlled, one of the biggest problems which still remains to be solved is that of parasitic plating. In the typical electro-plating process, the article to be plated is supported on an arm, or a plurality of arms, of a plating rack which moves along a conveyor and serves to dip the articles into an electrolyte bath. Since by the nature of the process the article serves as an electrode, in order to make an electrical connection to the article, the rack is by necessity an electrode also. Thus, when plating of the article occurs, any portion of the rack which is also in contact with the electrolyte bath is plated also. The rack eventually collects so much parasitic plating it becomes useless, and it is necessary to either destroy the rack or remove the plating so that the rack can be reused.
One solution to this problem of parasitic plating has been to cover essentially all that portion of the rack which is submerged into the electrolyte bath with an insulating material such as a plastisol. The portion of the rack arm upon which the article is supported, is left bare, of course, so that the necessary electrical connection between the article and the rack is completed. While this has substantially reduced the amount of parasitic plating, parasitic plating still occurs at the junction of article and the plating rack. In fact, under certain circumstances, it is still necessary to remove the parasitic plating from the rack as often as every two or three trips through the plating bath.
It is clear, therefore, that the electro-plating process can be made much more economical if the parasitic plating problem can be greatly minimized.