Visual Guide: Preparing and Reinforcing a Bumper

See step-by-step visuals of cleaning, sanding, and reinforcing bumper damage. Our images detail the transformation from surface preparation to fibre mat application, helping you ensure strong resin adhesion and long-lasting repairs.

Step 1: Prepare and Clean the Damaged Area

Begin by thoroughly washing the bumper to remove dirt, grease, and road debris. After cleaning, dry the area completely. Next, use 80–120 grit sandpaper to sand around the crack, split, or hole—aim for 3–5 cm beyond the damaged edges. This rough surface helps resin and fillers bond securely.

Wear gloves and safety glasses to protect yourself from dust and resin splashes. Use a clean rag with acetone or a suitable degreaser to remove any remaining contaminants.

Step 2: Assess and Reinforce Structural Damage

Check if the damage is superficial or goes through the bumper. Superficial scuffs or minor cracks can often be handled with putty; larger cracks or holes require reinforcement. For substantial repairs, reinforce with fibreglass mat for larger or structural repairs. Cut the fibreglass mat to size, ensuring it overlaps the damage by at least 2–3 cm all around.

If you are reinforcing a larger area, follow the instructions in your Resin Fibreglass Repair Kit – Complete Polyester Resin and Hardener Set for preparing and saturating the fibreglass mat. Apply the mat on the rear or interior side when possible for a smooth exterior finish.

Step 3: Mix and Apply Resin or Filler

Select the correct repair material: for deep cracks, holes, or missing sections, use a fibreglass repair kit; for surface imperfections or small dents, a CROP 2K Fiberglass Putty is ideal. Carefully mix the resin and hardener as directed. Mix only the quantity you can apply within working time, as these products cure quickly.

Apply the mixed resin or putty smoothly using a plastic spreader. Press firmly to fill the entire damaged area. Build up layers if necessary, letting each layer cure before adding the next. For a quick bonding of small cracks or returning tabs, “FixExpress” – Two-Component Epoxy Glue 500g can provide fast adhesion.

Step 4: Sand, Finish and Prepare for Paint

Once the resin or putty has fully cured, sand the area starting with 120 grit, progressing through finer grades up to 600 grit for a perfectly smooth surface. Sanding is essential for a strong bond between the repair and primer. Remove all dust before priming the bumper for paint.

For a visible or exposed repair area on a composite bumper, you may wish to apply a thin layer of “Carbon Resin” – Epoxy Resin for Carbon Fiber & Fiberglass Coating for additional gloss and impact resistance before final sanding and painting.

Before and After: Resin Bumper Repairs

Compare damaged and fully restored bumpers after resin repair. Clear images of completed projects show how careful restoration and finishing deliver seamless, robust results, returning your car’s bumper to peak condition.