Scratches can occur on the front or rear plastic bumper of your vehicle. Repairing these scratches isn't as difficult or as important as repairing scratches on sheet metal, since the plastic can't rust. Repairing scratches on a bumper can be done easily by following a few steps.
Sand the scratch with 120 grit sandpaper until it is smooth with no hard edges. Be careful not to sand too much in one area, as plastic is softer than metal and can be sanded too much, resulting in a low spot on the surface.
Spray two light coats of primer on the sanded area. Allow each coat of primer to dry for 30 minutes.
Sand the primer lightly with 300 grit sandpaper until it is smooth to the touch. Wipe the area with wax and grease remover to get rid of dust particles and oil from your fingerprints.
Spray two to three thin coats of paint directly on the scratch, holding the spray can or gun about eight inches away from the surface. Allow each coat to dry for 30 minutes before applying the next coat.
Apply two coats of clear coat paint, using the same technique as with spraying the paint. Allow the clear coat to dry completely before driving the car. This can take up to 24 hours.
A dual action air or electric sander can be used to speed the process, but must be used carefully so it doesn't burn through the plastic too fast.
Never spray primer or paint without using a respirator mask.