Plastic bumpers are designed to be flexible. The idea is that when they are "bumped" they have enough give and take to handle the blow and then pop back in place. Unfortunately, the theory may not work so well for the paint. Minor accidents, run-ins with a shopping trolley, or parking too close another car or object can cause damage to the paint on your bumper. The good news, however, is that repairing damaged or cracked paint on your bumper is something that you can easily do at home. Home repair is a much more economical way of repairing your bumper.
Fill a bucket with warm water and soap. Thoroughly wash the bumper with a sponge to remove dirt, grime, and debris. Rinse the bumper with a garden hose and dry it with a soft towel.
Remove the bumper from the car. Bumpers are held in place by nuts and bolts. The exact manner in which the bumper is secured to your vehicle depends upon the make and model of your vehicle. The screws may be hidden or obscured. Place the bumper in a warm and dry work area once it removed from the vehicle. A warm, dry climate is better environment patching material and paint.
Sand the damaged painted areas of the bumper with 60 grit sand paper. Sand the cracked paint until it is even and smooth with the surrounding areas of the bumper.
Fill cracks with a flexible auto filler. Plastic bumpers are made from a variety of materials. Look for a stamp on the rear of the bumper that identifies the material used for your bumper. The stamp will be two or four digits such as PP, PPO, PUR, or TPUR. Fill the cracks with the filler and allow it to dry. Sand the repaired area with 80 grit sandpaper. Wipe the bumper with a tack cloth to remove dust.
Lightly sand the entire bumper with 120 grit sandpaper. The goal is to roughen the surface of the bumper to allow better adhesion for the paint.
Apply several light coats of automotive primer to the bumper. Hold the nozzle six to eight inches above the bumper and apply the primer using back and forth motions. Apply the primer smoothly and evenly. Applying several light coats prevents the primer from running and dripping. Allow the primer to dry between applications.
Lightly sand the primed bumper with 400 grit sandpaper. Wipe the bumper with tack cloth to remove sanding dust.
Apply several light coats of the base colour to the bumper. Follow the same technique used for applying the primer coat. Allow the paint to completely dry overnight.
Reattach the bumper to your vehicle.
Polish the bumper with a rubbing compound and soft cloth. Buff the bumper until it has a glossy sheen.