When do-it-yourselfers attempt to refinish metallic surfaces with paint, peeling and flaking often result. The cause is inadequate or improper surface preparation. Metallic surfaces are notoriously ill-suited for paint adhesion. If you paint underprepared metal, expect rampant paint failure. Promote paint adhesion by pretreating the metal with a special acid-based primer formulated with the ability to etch metallic surfaces. Once the metal is properly conditioned, apply a durable coating, or you may end up with cracking and fading.
Scrub the metal with a trisodium phosphate cleanser, using steel wool. Rinse exterior metal, using a pressure washer. Use wet rags to rinse interior metal. Wait two to four hours for the metal to dry.
Coat the clean metal with galvanised metal etching spray primer. Promote a smooth, professional finish by maintaining an 8-inch distance between the metal and the spray nozzle at all times. Wait four hours for the primer to dry.
Coat the primed metal with acrylic spray enamel. Maintain an 8-inch distance between the metal and the spray nozzle at all times. Wait four hours for the enamel to dry.
You may use a roller and paintbrush to apply primer and paint to large metallic surfaces.
Do not paint unprimed metal, or the paint will peel. Do not use latex, acrylic or oil primers on metal, or the final finish will ultimately flake. You may use ordinary latex paint on interior metallic surfaces; however, do not use it with exterior metal, or cracking and fading may result. Be sure to degrease the metal, using a heavy-duty trisodium phosphate cleanser, or you will have problems with adhesion.