Unlike wood, stainless steel is nonporous, making it ill-suited for regular primer and paint adhesion. Painters must abrade stainless steel to encourage paint adhesion, or the finish will chip and peel over time. Unfortunately, because steel is so hard and durable, it cannot be abraded with friction techniques. Instead, a special type of metal-etching primer will condition the surface to accept paint. Once the proper primer is in place, any type of paint will bond to steel—although a specific type of paint works best.
Preparation is critical to promoting adequate paint adhesion. Stainless steel should be washed with a water-based degreasing agent before the application process begins. Soap and degreasers must be thoroughly rinsed, as they can interfere with adhesion.
Before any paint is applied, stainless steel should be coated in a galvanized metal-etching primer, using a paintbrush manufactured for latex paints. After the primer cures for 4 to 6 hours, painting can begin.
Although virtually any type of paint will bond to a properly prepared stainless-steel surface, a two-part epoxy paint is the preferred coating. It provides durability and an attractive sheen.
Because stainless steel is so slick, professional painters often dilute the paint with 1 ounce of water to every gallon of paint. This helps promote a smooth, professional-looking finish, free of unattractive brushstrokes.
Stainless steel should never be painted unless it has first been abraded with a galvanized metal-etching primer. No other type of primer will promote adequate adhesion. Never paint over an unprimed stainless-steel surface, or the finish will chip and peel soon after application.