To fix pitted metal, whether it is a fender, image frame or decorative item for your backyard, head to a car parts shop. Pits in metal are somewhat more unattractive, this corrosion may weaken the metal. Painting over corroded metal ends in paint failure, and it may seal in small rust particles that will erode the alloy farther. Repairing pitted metal is similar to smoothing imperfections out onto a wall socket, but the goods are designed specifically to use metal and inhibit rust. The substances used are poisonous, so apply protective eyewear, gloves and a face mask when sanding and applying paint or chemicals to metal.
Wrap a sheet of 80-grit sandpaper around a sanding block and sand the pitted area harshly. You can use a power sander rather than sanding by hand, but it might eliminate too much substance and weaken the metal. If the metal thing is very heavy, you may likely sand using a power sander.
Wipe the sanding dust off the alloy using a rag.
Scrub the alloy using a wire brush to remove rust particles from inside the pits and wipe off the particles using a dry rag.
Dampen a rag with alloy conditioner, which is a harsh chemical that removes the last traces of rust and prepares alloy for filler. Wipe off the conditioner with a clean rag until it dries.
Mix the right ratio of two-part auto body repair filler and hardener, as determined by the item instructions, within an old scrap of wood or metal, and combine the two components together using a plastic putty knife until they are smooth. Two-part filler cures fast — sometimes within minutes — so blend the substances immediately before use and operate quickly.
Scrape up the blended filler on the border of a plastic putty knife and spread it over the metal that is matched. Drag the edge of the knife over the surface to eliminate the excess filler, leveling the pits to be with the remainder of the metal.
Allow the filler harden for as long as the manufacturer recommends. Oftentimes, filler is hard enough to sand within minutes.
Sand the metal and hardened filler using a sanding block and 80-grit sandpaper, if needed, and wipe off the dust with a dry rag. Sanding with coarse sandpaper is just necessary if you were unable to scratch the excess filler evenly, that leaves ridges and bumps of filler onto the alloy.
Sand the whole metal bit using 400-grit, wet-sanding sandpaper and a sanding block. Mist water from a spray bottle on the alloy before pruning to lubricate the sandpaper and add more water as needed to keep the sandpaper and metal wet.
Sand again to get an ultra smooth finish, if desired, using 600-grit wet-sanding sandpaper and a sanding block.
Wipe off the sanding dust and dry the alloy using clean rags before employing rust-proof primer and metal paint.