How do you go about stripping nickel and gold from aluminum substrates? N. E.
I am assuming that the gold is plated over the nickel. Probably the most common way of stripping the deposits from the substrate is to use a 15–75% solution of concentrated nitric acid. The nitric acid should not have any effect on the aluminum as long as there is no chloride ion present in the solution. Of course, the nitric acid will not strip the gold deposit but instead will undercut the gold when it attacks the nickel layer. Personally, I recommend that you purchase a proprietary nickel stripper. In my experience, they work better than “home brews.” You can find suppliers of such materials in the Products Finishing Directory and Technology Guide, 2005, (800) 950-8020, under Stripping Solutions. Or better yet, you can find vendor information in pf's suppliers directory.