How to Bang out a Bumper

Some fender dents are so bad, entire replacement is a better option.

When a dent appears on your car bumper, whether metal or plastic, the dent sticks out like a sore thumb. While it may be too small to kick out large amounts cash for a mechanic to repair, the dent still reminds you that your car is now less than perfect. Fortunately, bumper repair consists of techniques you can perform in your own garage. With a few basic tools and some elbow grease, you can restore your car bumper and get rid of those annoying dings and dents.

Things You'll Need

• Crescent wrenches
• 220 grit sandpaper
• Spreader
• Bondo or filler
• Filler hardener
• Automatic sander
• Masking tape
• Primer spray paint
• Color spray paint
• Towel
• Wood block
• Table grinder
• Rubber mallet
• Wax and polish

Instructions

Plastic Bumpers

1. Get under the car and disconnect the plastic bumper if the dent is larger. Use a crescent wrench to disconnect the bumper attachments from the inside of the unit.

2. Use a 220-grit sandpaper and sand out the area of the bumper that is damaged. Expand the sanding to a radius of 2 or 3 inches around the damage. Continue sanding until the plastic appears without paint.

3. Use a plastic spreader to scoop up and spread a dollop of Bondo into the dent after mixing the filler with hardener. Insert and spread the filler until it generally fills up the cavity in the bumper. Try to smooth the filler to match the shape of the bumper. Perfection is not necessary; you just need to spread the filler to generally match the bumper surface.

4. Allow the filler to harden for 30 minutes to an hour. Check with your finger that the filler is now hard. Sand it down to match the surface of the bumper using the 220-grit sandpaper and an electric sander.

5. Wash the area and dry it off with a cotton towel. Let it dry. Square off the area with masking tape well into the original paint surrounding the repaired spot. Spray the area with a primer. Let the primer dry for 20 minutes. Spray a matching color spray paint that is consistent with your bumper color. Spray evenly and apply two or three coats. Let it dry.

6. Remove the masking tape after the paint has dried. Wax and buff the bumper to remove the transition of new paint to old paint. Reinstall the bumper to the car if it was removed.

Metal Bumpers

1. Remove the metal bumper from the vehicle if the dent is large. Use a crescent wrench to loosen and disconnect the bumper from the car frame.

2. Lay the bumper on a work table with a thick towel underneath.

3. Take a hand-size block of wood and use a table-grinder to shape it to how the internal curve of the bumper should look. Use a different part of the bumper to match the wood to. Grind until the wood shape matches the inside curve.

4. Place the wood into position against the dent inside the bumper. Hit the wood carefully but firmly with a rubber mallet. Continue the impact until the dent gets knocked out. Repeatedly check progress on the other side of the bumper. Continue until the dent is fairly knocked out or when you are satisfied with the progress.

5. Wax and polish the chrome side of the metal bumper. Reinstall it back on the vehicle.

Tips & Warnings

• Patience is the key to success with both plastic and metal bumpers. If you rush the job, you will likely make a mistake, damaging the bumper further.

• Never hit a metal bumper from the outside. This will not only knock a dent in further, but it will also crack and flake the chrome surfacing.

References

• Autos.com: How to Repair a Dent in a Bumper
• Autos.com: How to Repair a Plastic Bumper
• US Autoparts: Step-by-Step Instructions for Bumper Repair
• Automedia: Chrome Job – Tips on Getting the Shiny Bits to Look Right