Q. I have a slightly unusual application for electroplating: I want to plate a pattern onto the metal cathode, moving a sharp/pointy anode around to trace out the pattern (a non-conductive mask is not possible). However, I can’t decide what metal to plate and what solution would be best. I have attempted to plate copper using copper sulfate solution at 237 g/L onto stainless steel, and using a sharp wire as the anode. It has not been very successful so far. Are there any tips you can give with regards to the best materials and solutions? The anode material will likely be platinum, and we do not want it to be consumed in the reaction.—G.M.
A. This is an interesting idea, however stainless steel is not the easiest to electroplate because it has oxides on the surface that must be removed before you can get a deposit to adhere to that surface. To start your experimentation, you should use a material like copper or even a typical industrial steel as your base material. Then this base material must be thoroughly cleaned so no oxides are on the surface.
There is a process that is routinely used in the plating industry known as brush plating or selective plating. In its simplest form, you use a stylus to plate metal on surfaces that normally cannot be plated in a plating tank. The process is also used for field repair. Normally, a wider stylus or brush is used, but I see no reason why you couldn’t use a narrow, pointy stylus.