I have done some research and asked in a few forums for gold plating on anodized aluminum and stainless steel but haven't yet found the answer to my questions.
What are the chemicals for pre-processing the surface and the suitable gold solution for these tasks?
For stainless steel I believe they use Wood's nickel for pre-processing. Is it the only or the easiest method? How about anodized aluminum?
Both materials you have selected are not good candidates for electroplating because they both protect themselves already with an oxide coating. "anodized" is referring to an intentional increased amount of surface oxide to protect the metal. This oxide must be removed, so you really want to ask "how to gold plate aluminum" not anodized aluminum. In order to plate them you have to go through an acid pickling process that removes the oxide, then nickel plating(has better adhesion), then gold plating.
I am not an expert and there are may steps involved especially for high quality finishes. I recommend asking your question here (Caswell > Electroplating Questions).
