How to Repair Broken Fiberglass

Fiberglass repairs typically fall into one of two categories: repairing holes and fixing cracks.

Each repair is similar to the other, but there are a few minor differences. Whether your garage door panel is cracked, or there is a hole in the hull of your fiberglass boat, this repair method solves the problem. Making it look like new again is not out of the question. However, it requires skill and practice to make repairs absolutely flawless.

Assess the damage and remove loose or broken off shards of the fiberglass by cutting them away with a knife or jigsaw, so you are left with a smooth, nearly geometric hole in the fiberglass.

Sand the area around the hole and bevel the edges with sandpaper or a grinder, if the damage encompasses a large area. The entire edge of the hole should be beveled to accept the fiberglass patch repair.

Cut strips of fiberglass to fit over the hole by laying them on the hole and trimming away excess, leaving an inch or two of overlap onto the fiberglass. If the hole is very large and the fiberglass sheets drop into the hole, cut a sheet of laminate slightly larger than the hole and apply PVA (polyvinyl alcohol) to the surface facing your repair. Attach it underneath the repair area with strong duct tape.

Lay the fiberglass sheets over the repair area. Mix the resin with the hardener in your fiberglass repair kit, and apply the fiberglass resin to the sheet. Spread the resin over the entire sheet in generous amounts so the entire area, including the overlap is covered in resin. Let this dry for several hours or until the entire surface is solid.

Sand the repair to make it flush with the rest of the fiberglass, using 200-grit sandpaper. For large areas use an orbital sander and pad. Add primer to the repair area and let it dry. Add a top coat to finish the repair.

Things You Will Need

  • Knife or jigsaw
  • Sandpaper, 100 or 200 grit
  • Fiberglass repair kit (includes fiberglass sheets, resin, applicator and hardener)
  • Laminate
  • Polyvinyl Alcohol or mold release compound
  • Oribital sander (optional)
  • Primer
  • Paint

About the Author

Steve Smith has published articles on a wide range of topics including cars, travel, lifestyle, business, golf, weddings and careers. His articles, features and news stories have appeared in newspapers, consumer magazines and on various websites. Smith holds a Bachelor of Arts in English and journalism from University of New Hampshire Durham.