Ask the Expert Question-and-Answer Archive

by Ron Joseph

May, 2003

Zinc-Rich Primers

Q. In your Question and Answer archive you discuss inorganic zinc-rich primer comes in two parts. Where might I purchase some, initially to evaluate it? Also for evaluation, would it be practical to vary the ratio of resin to zinc powder to e.g. 85%to 95% zinc.

A. Thanks for your question. You can purchase zinc-rich primers from companies such as Sherwin-Williams, PPG, Carboline, Ameron and other manufacturers who cater to the maintenance

paintng field.

As you increase the zinc dust content, you will get to a point at which there is too little resin to wet and hold onto the zinc. Without sufficient resin adhesion of the primer to the substrate will deminish. The currently available inorgranic zinc-rich coatings are already so saturated with zinc powder that it is difficult to apply them and maintain a wet coating. Without looking at a data sheet, I don't know what the current zinc loading is, but in my opinion if you try to add even more zinc, you are quite likely to fail.

When you have completed your experiments, please get back to me with your findings as I'm always intrerested.