Experts recommend using oil-based paint or high-quality 100 percent acrylic latex paint for painting steel surfaces, while flat- or satin-finished paint is more suitable for aluminum. With proper surface preparation, spray paint in a rust-resistant or multipurpose formula is suitable for both steel and aluminum surfaces.
Steel tends to rust, so experts advise using a wire brush to remove any rust prior to painting steel surfaces. When painting steel, one to two coats of rust-resistant specialty primer used before the application of a top coat of paint prevents rusting of the metal when exposed to oxygen and moisture. One coat of primer is sufficient, but two coats extends the durability of the top coat.
Professionals recommend cleaning the surface of previously painted aluminum with a cleaner, such as trisodium phosphate, to create a better surface for the application of paint. Painters should use flat- or satin-finish 100 percent acrylic latex house paint on aluminum, since glossy paint accentuates surface dents.
When opting to spray paint steel or aluminum, experts suggest preparing the surface by priming it first with rust-resistant primer. This helps the top coat to adhere more effectively to the surface. Professionals advise using rust-resistant or multipurpose enamel spray applied in several thin coats.