Car wheels receive the most abuse and punishment from the road than any other part of the car. Hitting potholes, curbs and other objects can cause "curb damage" to the sides of your aluminium alloy rims. If not fixed, the damage can rust the wheel and eventually reduce the integrity and strength of the rim. Always try to repair curb damage as soon as it happens to prevent rusting. While this process can be performed while the wheel is on the car, it is easier to do when it's removed.
Clean the wheel thoroughly using a towel and car soap. This will result in a better looking repair job and prevent you from getting dirt and brake dust on your hands. Allow the wheel to dry before repairing any curb damage.
Soak a towel in paint thinner and rub it onto the damaged part of the wheel. This removes everything that washing missed as well as any wax that is present on the wheel. Wash the rim twice to remove any excess paint thinner. Allow the wheel to dry.
Place masking tape around the damaged parts of the rim to prevent you from using sandpaper on undamaged areas of the rim.
Gently sand the damaged part of the rim using 400 grit sandpaper. Allow grooves to form and stop once the area is rough.
Cover the scratch with Bondo putty and smooth with 600 grit sandpaper. Allow to dry for five minutes. After five minutes, sand the area gently with 600 grit sandpaper and allow it to dry for another five minutes.
Cover the rest of the wheel and tire with masking tape to prevent overspray when you apply the aluminium paint. Apply thin layers of paint and allow to dry until the Bondo is completely covered. After the paint dries, gently use 1,200 grit sandpaper to further smooth the surface of the repair site.
Wash the painted area of the wheel with car soap and water and allow to dry.
Spray the clear lacquer onto the repaired part of the wheel. This will protect your repair job and make it shiny to match the rest of the wheel. Repeat this step five times to build up a strong barrier. Remove the masking tape from the wheel and allow the lacquer to dry overnight. Once the lacquer is dry, wash the wheel again to finish the repair job.