Protecting Glass Mirrors

Question:

We produce silvered glass mirrors in all shapes and sizes. We are toying with an application for using a mirror outdoors. Corrosion will be a problem, so we need to protect the back. Could you suggest a paint coating or coatings that will protect silvered glass mirrors from corrosion in an outdoor environment? K. M.

Answer:

I know very little about mirrors. In fact, I try to avoid them. One look at my photograph in Painting Clinic will tell you why. Since you need corrosion resistance, I suggest applying a two-component epoxy primer to the silvered back of your mirrors. Another paint to consider is a two-component polyurethane. Actually, any moisture-resistant paint having excellent adhesion is a good candidate. The surface must be clean (free from oily soils, polishing and grinding compounds, as well as loose particulates) and dry before painting. It is important that the paint be applied beyond the edge of the silvering, so that moisture does not creep under it.