Powder coating is a type of paint finish used on metals such as aluminium. You can paint powder-coated aluminium to create a new colour or look for items such as outdoor furniture, aluminium windows or siding and vehicle parts. Powder-coated aluminium has been etched, so you do not need re-etch the metal again, saving a step in the pre-treatment process.
Consider the elements that the aluminium you are painting is exposed to. Choose an anti-rust latex or oil-based paint. Pick a type of finish such as matt for a flat finish or semigloss or glossy for a shinier finish.
Decide on how to apply the paint. Use a brush or spray paint can for small surfaces and a spray gun for larger surfaces. Applying paint with sprays allows even distribution of the paint on the aluminium surface.
Place gloves on your hands. Wear protective eyeglasses to prevent chemicals and paint from getting into your eyes. Wear a mask over your nose and mouth to providing safety from chemical inhalants in the products you are using throughout the cleaning and painting process.
Dilute the liquid alkaline solution in water, based on the amounts indicated on the back of the liquid alkaline bottle. Dilute small amounts of the mixture in a bucket or large amounts of the mixture in the washer part of the high-pressure hose.
Apply the aluminium-safe liquid alkaline cleaner to your aluminium piece to remove dirt, debris and oil. Liquid alkaline acts as a degreaser that cleans the aluminium surface in preparation for painting while preventing against rust and corrosion. You can apply it by dipping a sponge or towel into a bucket for small aluminium projects or by pouring the liquid alkaline and water mixture into a high-pressure hose for larger projects.
Allow the aluminium to dry in the sun or dry it off with a clean towel. Wait until the surface is dry. Waiting time varies based on the size of the aluminium surface. For example, aluminium siding on a house may take 24 hours to dry while an aluminium chair may take one hour to dry.
Spray paint a small part of the aluminium to test the paint colour. Allow the paint to dry so that you can see what the final appearance is. Determine if you are satisfied with the colour, texture and finish of the paint.
Tape around areas that you do not want painted, such as windows or tires, with painter's tape. Cover and tape the areas with newspaper or plastic bags to prevent paint speckling.
Paint a first coat onto the aluminium with a brush or sprayer. Allow the first coat to dry in the sun for four to five hours. Face fans toward the painted aluminium to speed the drying process (an optional step).
Paint a second coat onto the aluminium. Follow the drying instructions from the previous step.