How to Apply Epoxy to a Stripped Fiberglass Hull

Over time fiberglass hulls wear from weather and must be recoated with epoxy.

A fiberglass boat hull is inexpensive and aesthetically pleasing, but, epoxy will corrode over time. Boats are often made from fiberglass due to its high strength-to-weight ratio and low cost. In order to keep the boat hull strong, stripped fiberglass areas should be recoated with new epoxy resin.

Things You'll Need

• Lab coat
• Safety glasses
• Nitrile gloves
• Fiberglass hull or boat
• Boat trailer
• Rough grit sand paper
• Epoxy resin
• Polyethylene cup
• Wooden stir rod
• Epoxy spreader
• Fine-grit sand paper.
• Clear coat composite sealant

Instructions

1. Dress in a lab coat, safety glasses and nitrile gloves to keep epoxy off your body and clothing.

2. Remove the boat from the water if necessary and allow it to dry on its trailer.

3. Sand the boat hull or the area to be repaired with rough-grit sandpaper. Make sure that the area being repaired is rough. This will insure a strong and deep bond between the new epoxy resin and the old epoxy resin and fiberglass. The hull can remain on the trailer for the entire process. If the boat hull is separate from the rest of the boat, then it is easier to flip the hull over so that you can lean over it instead of under it.

4. Mix epoxy resin in a polyethylene cup with a wooden stir rod.

5. Spread the epoxy resin onto the repair areas with an epoxy spreader. Make the area slightly higher than the surrounding area. After the epoxy cures you will sand the epoxy smooth and fit it to the surrounding area.

6. Sand the epoxy smooth and level with the surrounding area. Attempt to give the repair area the same contour or curve as the boat while sanding. Rough- or medium-grit sand paper should not be needed before this step; typically epoxy cures fairly smoothly.

7. Apply a clear coat composite sealant to the entire hull. This will protect your hull from scratching, corrosion and other weathering. U.S. Composite's "Kleer Kote" sealant is an efficient coating that will help protect your hull from weather and UV light. Allow the clear coat composite sealant to cure for the time designated by the manufacturer.

Tips & Warnings

• Vacuum bag your hull if it is small enough. This will give you a stronger bond and a better strength-to-weight ratio.

• Try other coatings instead of a clear coat. Consider a gelcoat, which is attractive and resistant to many forms of weathering.

• Use nitrile gloves instead of latex. Some people are allergic to latex and latex also falls apart when in contact with certain chemicals used in composites.

References

• Fibre Glast Learning Center: About Fiberglass and Composite Materials
• U.S. Composites: Kleer Koat #30

Resources

• U.S. Composites
• Chesterton: Composite Coatings
• Fiberglass Supply: Gel Coats