Contrary to what many people believe, aluminium actually can rust. Cast aluminium is a denser form of aluminium that has some of the properties of aluminium and some of the properties of lightweight aluminium. Cast aluminium is used for furniture, cars and other metal objects that need to be tough and lightweight. Over time, exposure to air and moisture will cause the aluminium to corrode. You can remove and repaint the metal to prevent further damage to the metal and to make the metal usable once more.
Put on a dust mask and eye protection to prevent inhaling metal dust and to prevent the dust from getting into your eyes. Spray the metal with a spray paint remover designed to remove paint from metal. Allow the remover to sit on the aluminium for about 10 minutes. Wipe away any remover residue with a soft cloth.
Sand the entire surface of the cast aluminium with the rust-removing sanding pad to remove all signs of corrosion and rust. Allow the aluminium to sit overnight. The paint remover will remove any paint and rust from hard-to-reach areas overnight.
Sand the metal with one final set of sanding using a fine-grit sanding attachment. Wipe down the surface of the aluminium with a damp cloth to remove paint and metal dust.
Spray the metal with an aluminium primer. Allow the paint dry for two hours, then apply a second coat of aluminium primer. Allow this coat to dry for two hours as well.
Spray the aluminium with the rust-resistant paint. Paint a total of about three coats of paint onto the metal, allowing each coat to dry for at least an hour between coats.