How to repair a bumper?
Did someone accidentally bump into you in the supermarket parking lot? Was that pesky utility pole closer than you thought? Whatever the reason, it's not uncommon for a car's bumper to show a few dents after years of use.
The amount of impact absorbed by the bumper determines whether it is repairable or not. Some bumpers tend to warp, while others tend to crack. Fortunately, both types of damage are almost always repairable, unless the damage is really too extensive. If the bumper has a large number of cracks, or if too much of it is missing, it may make more sense to replace the entire bumper.
You'll usually need to determine the extent of damage to a body. Most offer free repair estimates. But before you accept a quote and let a body shop repair your car, there are several very simple methods for repairing a car bumper yourself, using a few tools you may already have at home.
Plastic or Fiberglass Repair Kits
The contents of bumper repair kits can vary, but in general they should include
- A product to clean the surface to be repaired
- A filler to fill cracks
- Primer to optimize adhesion of new paint
- Paint to maintain the appearance of the vehicle
Bumper repair kits are not designed for major damage. If your bumper is badly damaged, it's best to order a new bumper or even a complete bumper from MOSTPLUS. We have a wide range of high quality front and rear bumpers for many car makes at low prices.
How to repair a cracked bumper?
STEP 1: Clean and Prepare Surface
Remove any heavy dirt and rinse the plastic part thoroughly with clean water. Clean and prep the area to be repaired with the cleaner and a lint-free cloth.
STEP 2: Prepare damaged areas
For cracks, drill holes at the ends of the crack. The diameter of the hole should be approximately 6 mm to prevent the crack from spreading. Widen the crack to leave a gap of at least 2-3 mm. If there is a hole, go directly to step 3.
STEP 3: Milling
Make a V-shaped chamfer on the edges of the outside of the area to be repaired. The holes at each end should also be V-beveled using a sander.
STEP 4: Sand
Sand the surfaces on both sides with P150 grit paper, removing any sanding debris. Don't forget to sand the inside of the damaged area. Clean and pre-treat both sides (inside and out) with cleaner.
STEP 5: Fiberglass Preparation
Cut a piece of fiberglass to size (at least 1 cm wider than the damaged area). Remember to cut off the ends of the fabric to prevent fraying.
STEP 6: Apply Primer
Spray a thin coat of primer on both sides (front and back). Allow to evaporate at room temperature for approximately 10 minutes.
STEP 7: Cartridge Preparation
Open cartridge and squeeze out a small amount of product until both components flow simultaneously. Attach the mixing nozzle and discard the first 2 inches of mixed adhesive.
STEP 8: Interior Application (1/2)
Apply the quick-setting Plastic Repair Adhesive to the interior surface around the area to be repaired. Position the cut fiber over the area to be repaired and apply pressure to the fiber with a spatula to allow the product to penetrate the fiberglass.
STEP 9: Interior Application (2/2)
Apply adhesive over the fiberglass and spread until the repair area is completely covered. Hold the nozzle in the adhesive to prevent air bubbles.
STEP 10: Cure
Fast Cure Plastic Repair Adhesive will be touch dry in 2-3 minutes at room temperature. To speed up the curing process, it is recommended to increase the temperature to 60-70°C. Mixing time: Approximately 2 minutes. Ready for sanding: 10 min.
STEP 11: Exterior Application
Apply the quick-setting Plastic Repair Adhesive to the exterior surface, keeping the tip of the nozzle in the product to avoid air bubbles. Smooth with a spatula, working from the center of the damaged area outward.
STEP 12: Cure
The fast setting Plastic Repair Adhesive will be dry to the touch in 2-3 minutes at room temperature. To accelerate curing, we recommend raising the temperature to 60-70°C. Mixing time: Approximately 2 minutes. Ready for sanding: 10 min.
STEP 13: Surface preparation (1/2)
Sand the repair area to smooth the surface and clean with Surface Preparation and a lint-free cloth.
STEP 14: Surface preparation (2/2)
Apply a thin coat of primer for optimum adhesion. Allow 10 minutes for the primer to evaporate. During this evaporation time, mix the Plastic Filler with the Hardener (ratio: one golf ball to one pea-sized amount of Hardener).
STEP 15: Apply Plastic Filler
Apply the mixed putty to the repaired area and spread evenly. The surface can be sanded (after about 30 minutes) and is ready for painting. If you want to be able to sand after 15 minutes, you can accelerate the polymerization by placing a drying lamp 1 m from the workpiece.
STEP 16: Painting
The bumper is now ready to be painted, following the recommendations and instructions of the paint manufacturer.
How do I repair a dented bumper?
- Step 1: Raise the vehicle and support it with candles. To safely place the stanchions, make sure they're on a stable surface. Use a jack on the undercarriage rabbets to raise the vehicle, then place it on the stanchions.
- Step 2: Remove the engine cover. If your vehicle has one, remove the under-engine cover and/or wheel cover to gain access to the damaged area of the bumper. The underhood cover is held in place by plastic clips or metal bolts.
- Step 3: Heat the damaged area. Use a heat gun or hair dryer to heat the entire damaged area. Continue until the bumper softens. It should take no more than five minutes for the bumper to reach a sufficiently pliable temperature.
- Step 4: Remove the dent from the bumper. While you're heating the bumper, or immediately after, use a crowbar to straighten the bumper from the inside out. The deformation should gradually decrease as you press with the crowbar. If the bumper is still not flexible enough, reheat the damaged area to increase the flexibility.
Now you know how to fix a bumper! However, if your bumper is badly damaged and requires major repairs, it's best to leave it to a professional.