Galvanized steel is one of the most durable metals on the market and is used for everything from industrial structures to playground swing sets. One of its major drawbacks, however, is its susceptibility to corrosion. Luckily, properly cleaning and painting galvanized steel will keep the metal from wearing down. Professionals utilize three different methods when applying corrosion protection to steel: spray painting, hand painting and powder coating.
Before a drop of paint is applied in any form, each steel surface must be properly cleaned. The first step, no matter if the metal is corroded or brand new, is to sand it with a thick-grit sandpaper. Apply pressure until any bumps or irregularities are removed. Next, clean the entire surface with soapy water and rinse, letting the metal completely dry. Finally, purchase a galvanized metal primer and apply it to the entire surface.
With this preparation, any one of three techniques can be used for painting galvanized steel. The most popular method for a small project, like a swing set, is to spray paint the surface. There are several commercial paints, in many different colors, available for this job at painting supply stores. Simply spray the paint evenly over the surface until it dries. If runs or streaks appear, sand them down and reapply paint until smooth.
Larger jobs, like railings and walkways constructed from galvanized metal, require hand painting. Professionals recommend polyurethane, epoxy or enamel paint in order to best protect against corrosion. Using a brush or roller, apply the paint in even strokes so every aspect of the exposed steel is covered. Painting galvanized steel by hand usually protects the metal from the elements better than spray painting because the coating is thicker and more weather-resistant.
A third method for painting galvanized steel, usually reserved for large jobs, is called powder coating. The first step in powder coating is applying a layer of zinc across the entire metal surface. This application provides a protective buffer against weather and temperature, so the metal will not corrode easily. The second step of this process is blowing a powder over the zinc until it coats the entire metal surface and then heat curing it. The curing process bonds the powder to the metal and also brings out the chosen color of the powder.