How to Repair Fiberglass

Fiberglass is a covering material made of glass fibers encased in resins. The distinctive property of fiberglass is its strength – for this reason it is commonly used for structures such as bathtubs, boats, and garage doors. Below are step-by-step instructions on how to repair fiberglass that has developed a hole.

Required Materials

• gelcoat
• polyester resin
• fiberglass fabric
• fiberglass mat
• Methyl Ethyl Ketone Peroxide
• de-waxing solvent

Required Tools

• resin roller
• razor
• tape
• grinder

Instructions

1. Detecting the Fiberglass Damage – If the fiberglass damage is not plainly visible, you can detect damage by tapping the fiberglass with a hard tool. Normal fiberglass will emit a sharp sound when tapped. The damaged fiberglass will emit a dull sound.
2. Preparation – To get an unseamed finish after repair, it is advisable to start the repair work from the inner side.
3. Cutting the Damaged Area – Slice off the damaged area of fiberglass. Using a grinder, taper down the fiberglass hole. A good taper will further facilitate the quality of the final repair.
4. Using a De-Waxing Solvent – To strengthen the bond of the new fiberglass, treat the exterior edges with a de-waxing solvent.
5. Paste Wax Coating – Apply paste wax around the hole. The coating of paste wax ensures that any remaining resin stays away from the undamaged area.
6. Waxed Backer – The waxed backer will help you achieve a hard surface. Position a backer at the bottom of the hole with tape or a screw.
7. Using a Gelcoat – The waxed backer will need to be coated in a gelcoat. Since gelcoat is a pigmented resin, you will need to match the color of the coat with the color that is finally required.
8. Cutting the Fabric and Mat – Cut the fiberglass fabric and mat to equal sizes – the size of the hole – and place both in alternating layers. The density/thickness of the fiberglass will determine the amount of mat and fabric that will need to be used. Avoid using more than four layers, as this could begin to soften the bond.
9. Using Epoxy or Polyester Resin – Patch the fiberglass hole and firm up the mat and fabric with polyester or epoxy resin. A laminating resin will be required when using polyester resin to strengthen the bond.
10. Using a Catalyst – Use Methyl Ethyl Ketone Peroxide to strengthen the polyester resins. With the help of a resin roller, even out any air bubbles or uneven protrusions.
11. Removing the Wax Backer – After removing the wax backer, use gelcoat to fill up any flaws. Now sand and polish the area if required.

Tips and Warnings

• When working with fiberglass, proceed with caution; it can irritate the throat, eyes, and skin.

For more information Read

How to Repair Fiberglass

How to Repair Fiberglass