Zinc–Rich Primer Over Zinc Plating

Q. I am a process engineer for an electronics equipment supplier. We are presently outsourcing the production of some of our parts, but I would like to replace a current process of zinc plating with a zinc paint process on a steel chassis and bring its production in-house. Is this possible? We have both a paint line and powder line in-house. Also, can zinc paint be powder coated afterwards? Do you have any recommendations for a zinc paint? M.M.

A. In many cases, a zinc-rich primer can provide protection equivalent to zinc plating on steel. There are essentially two basic choices for a zinc-rich coating: a zinc silicate, which has an inorganic binder and is usually applied to shot- or sand-blasted steel; and an organic zinc-rich primer, which typically has an epoxy resin binder. Both can be recoated with powder coatings. Of the two, you should consider using the organic zinc-rich primer. The zinc silicate primer is usually applied to structural steel at a building site.

Your present paint supplier should be able to provide you with an organic zinc-rich primer, or look for suppliers on PFonline.com.