Most car bumpers are made from fiberglass, which is a durable material, until the car accidentally bumps against a collision. A bend or crack can ruin the look of any car. Fixing a fiberglass car bumper is easy and requires little car skills. Here is a look on how you can repair a cracked fiberglass bumper yourself:


Things you will need


  • Fiberglass resin
  • Fiberglass cloth
  • Sandpaper
  • Bondo
  • Mineral spirits
  • Grinder




  1. Remove the car bumper.
  1. If the crack is small, simply apply a layer of Bondo over it to repair it. If the crack is larger, follow the next steps.
  1. Clean the crack with mineral spirits.
  1. Mix the Bondo and apply it to the crack and around the outer area.
  1. Allow the Bondo to dry, and then sand it with the sandpaper. Use rough 60 grit first, and then move up to a 400 grit.
  1. Apply a fiberglass weave to the crack if it is larger than 1/16 of an inch.
  1. Grind the surface a few inches to both sides of the crack.
  1. Mix the fiberglass resin and apply it the crack on the backside of the bumper with a brush.
  1. Place a the fiberglass cloth on the resin, and ensure there is enough coverage to give proper support to the crack.
  1. Brush some fiberglass resin on the fiberglass mat.
  1. Let the fiberglass dry and sand the repair down until it is leveled.
  1. Use the Bondo to fill any imperfections that are visible. Sand with a 60-girt and go up till 100 grit to paint it.