Be sure to have the primer and spray equipment ready before you begin blasting or cleaning. Rust will begin to form on a bare metal surfaces within a very short period of time. Clean the surface with a surface cleaner just prior to priming. All surfaces must be cleaned and primed prior to painting. Epoxy primers come in a variety of colors.
Lighter colors are easier to cover with final topcoats, and produce brighter topcoats.
A word about zinc chromate primers- zinc chromate has been used for years as a primer. Zinc chromate should not be used if you plan to apply polyurethane paint. The elapsed time between priming and applying the topcoat will vary depending upon the brand of paint used. Different manufacturers recommend varying times. As a general rule, an epoxy primer should completely cure and harden prior to applying the top coat.