Repairing a Plastic Bumper
Because it takes less time, most body shops replace bumpers rather than repair them. But you can repair your cracked or broken bumper, if you desire. To do so, follow the instructions below. They can save you time, energy and money.
Purchase a bumper repair kit. It will include all of the sprays, solutions and other materials you will need. You can also purchase kits that have tools like heat and application guns, if your tool collection does not include them.
If the bumper is distorted, apply heat with your heat gun to soften the plastic; then return it to its original shape. Note: some plastic-type materials, like fibre glass, cannot be reshaped. Wipe all silicone and grease from the bumper with mineral spirits.
If the bumper is cracked or split, you will need to enlarge the gap to at least 3mm wide, but tapering to a point at the end. Use a hack saw, knife or multi-tool to make your enlargement.
With your electric or portable drill, bore a small hole, 3mm from the end of the crack. Drill additional holes 5mm apart along either side of the crack. The holes should each be about 3mm from the crack's sides. With a saw, make a "V" shape around the crack to about 30mm from the edge.
Spray some plastic cleaner on a soft cloth and wipe the broken area, front and back. Do not spray the plastic cleaner directly onto the plastic. After the plastic dries, evenly spray a coat of adhesion promoter, again both front and back. Allow about 30 minutes for the adhesion promoter to dry.
Use a scissors to cut a piece of contouring film of the appropriate size. Also cut a piece of reinforcing film. Test the adhesive gun by pumping some of the adhesive onto a piece of to paper. Use the gun to apply adhesive on the mesh part of the reinforcing film. Apply so there is enough to overfill the crack slightly. Remove the mixing nozzle from the gun and replace it with the end cap. You will have to use a new mixing nozzle next time.
Wearing impermeable gloves, push the reinforcing strip onto the back of the crack. Next, fill each hole that you drilled, starting from the narrow end of the crack. Slightly overfill the crack and the holes. Work fast because the adhesive dries quickly.
Press the contouring film onto the adhesive, but not into the crack itself. Try your best to follow the contour of the original plastic bumper.
After the adhesive has dried completely, remove the contouring plastic and the plastic backing of the reinforcing film. Sand down, then finish as usual