Ask the Expert Question-and-Answer Archive

by Ron Joseph

October, 2003

Painting Copper for Electrical Insulation

Q. Our customer's application involves a copper conductor (alloy 101 oxygen free) which must be electrically insulated and chemically protected while submerged in a concentrated acid or solvent bath. As such, we are looking for a suitable coating that results in a dielectric barrier with excellent adhesion and chemical resistance. The first thing that came to mind, aside from PTFE coatings, was to use Imron paint. However, these are not reccomended for immersion service. Any ideas to get the job done without resorting to expensive PTFE coating?

A. This is not a simple application, as you have already pointed out. Since you haven't told me what acid(s) and solvents are involved, I can't really give you an answer. However, there are paint companies that specialize in chemical and solvent resistant coatings. You might go to the website of Carboline Coatings (www.carboline.com) and look for their reference table in which they tell you what coatings can withstand immersion in specific chemicals. Once you have identified the coating, the next problem is to insure that the coating can be applied to the substrate to give you excellent adhesion. You might need to pretreat the copper with an etching primer, or an acid etch before coating it.

If you don't come up with an answer, please get back to me.