How to Repair a Fiberglass Sailboat Hull

How to Repair a Fiberglass Sailboat Hull
Sailboats like most other boats are constructed out of fiberglass. Fiberglass is a very durable and lightweight material that doesn't rust or rot like other boat building materials. Commonly from small accidents or just docking your boat, damage will occur to the hull. Unlike some people's belief, fiberglass damage can be repaired back to original strength when the correct process is followed. Fiberglass is applied in layers of reinforced glass material that is saturated with catalyzed resin. When repairs are done correctly they will completely blend in with the surrounding fiberglass and be unnoticeable.

Instructions

Difficulty: Moderate

Things You’ll Need:
  • Rubbing compound Rags Respirator Air grinder Acetone Fiberglass mat Razor knife Small bucket Fiberglass resin Catalyst Stir stick 4 Inch felt roller Air roller Palm sander 100-grit sandpaper 300-grit sandpaper Gel coat Gel coat spray gun Boat wax Electric buffer
  • Rubbing compound
  • Rags
  • Respirator
  • Air grinder
  • Acetone
  • Fiberglass mat
  • Razor knife
  • Small bucket
  • Fiberglass resin
  • Catalyst
  • Stir stick
  • 4 Inch felt roller
  • Air roller
  • Palm sander
  • 100-grit sandpaper
  • 300-grit sandpaper
  • Gel coat
  • Gel coat spray gun
  • Boat wax
  • Electric buffer
Step 1
Remove the wax from the surface of the damage using a rag and rubbing compound. Rub the area in circular motions until the shine is removed from the surface. Rinse the left over residue of the damaged area with water and let it dry.
Step 2
Put on a respirator and grind all the damaged fiberglass material down to solid fiberglass using an air grinder with a 36-grit sanding disk. Bevel the edges of the damaged area into a gradual slope to give the repair patch a large surface area to bond to. Clean the entire area with a rag and acetone.
Step 3
Cut the first layer of fiberglass mat so it overlaps the inside edge of the repair by 1/2 inch all the way around. Cut each following layers 1/2 inch larger than the last. Use as many layers as it takes to rebuild the damage back to it's original thickness. Make the finishing layer completely cover the damage.
Step 4
Add catalyst to a small bucket of resin following the recommendations on the containers. Thoroughly mix the catalyst into the resin using a stir stick.
Step 5
Wet the surface of the damage with the resin using a four-inch felt roller. Apply the smallest layer of mat directly in the center of the damage and saturate it with resin using the felt roller. Flatten the mat and remove any trapped air bubbles using an air roller. Continue this process for each layer of mat until the repair is complete. Let the fiberglass harden.
Step 6
Sand the repair smooth using 100-grit sandpaper on a palm sander. When the repair is completely level with the surrounding fiberglass and blended in, switch to 300 -rit sandpaper and lightly sand the damage. Clean the area with a rag and acetone.
Step 7
Add catalyst to a small bucket of pre-matched gel coat following the containers recommendations. Mix the catalyst into the gel coat using a stir stick. Pour the catalyzed gel coat into the gel coat spray gun.
Step 8
Spray the first coat of gel coat onto the hull repair in a heavy mist. Keep the tip of the gun a consistent distance from the hull for an even coat. Let the first coat harden and apply a second heavier coat to the hull. This coat should completely cover the damage but one more light coat can be added if needed. Let the gel coat harden.
Step 9
Apply a thick coat of boat wax to the hull of your boat using a foam applicator pad. Let the wax dry and buff it to a shine using an electric buffer.

Tips & Warnings

 
When working with fiberglass always wear a respirator to avoid inhaling glass fibers.
 
When working with fiberglass always wear a respirator to avoid inhaling glass fibers.

Article Written By Jay Kurz

Jason Kurz has been a published writer for eHow.com and Trails.com for less than a year now. Kurz attended Kent State University of Ohio for Computer Aided Design.

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