Galvanized steel has been coated with a thin coating of oil and passivator that protects it from water and weather damage. That’s great for preventing rust, but it also prevents solid paint adhesion. To paint galvanized steel, do your prep work and you’re going to have a paint job that lasts for seasons.
Sterile
Use a water-based degreaser to scrub off the surface and passivator coating. You’ll find many brands of degreasers available at any hardware store or home improvement center. Find degreasers in the cleanser darkened or marine region if your store has one. Some degreasers will need to be diluted with water, though others can be used full strength. Rinse thoroughly and allow to dry completely after you wash the surface down.
Sand
You just cleaned the oil off coating, but you should still sand the galvanized surface so the paint adheres well. Sand the surface with a sanding block, or save time and effort and use a drum sander or rotary tool with a sanding bit. Begin with an 80- or 120-grit sandpaper, then perform a second pass with 180-grit for a smoother finish. If you are pressed for time perform a single sanding with 80- or 120-grit sandpaper.
Prime
Steel primer is available as a spray or a liquid that you paint with a brush. Some may bypass the primer measure, but it offers an extra layer of protection against the elements and it creates a smooth undercoat for the paint. After you employ metal primer, let it cure according to the manufacturer’s directions. The primer should be completely dried and treated until you paint.
Paint
If you’ve primed your surface using a metal primer, you can use most acrylic paints to complete the job. For extra protection you can use a paint specially formulated for metal surfaces, but your primer provides the same protection. The choice is yours. Spray paint is among the most popular procedures of applying paint to a metal surface and there are numerous producers of spray paint to metal surfaces. Apply one or more coats of paint according to the manufacturer’s directions.
