How to Make a Fiberglass Keel
The keel of a boat is a common part that gets damaged because it's usually the lowest part of the boat. Keels from a fiberglass boat can be repaired or fully replicated using a mold. Molds for fiberglass can be made from an existing part or bought at marine supply stores. To fiberglass a mold you will first have to cover it with a layer of gel coat and then the layers of fiberglass mat. The mat is bonded together using a fiberglass resin that's mixed with catalyst. All fiberglass materials can be found at your local marine supply store.
Things You'll Need
- Keel mold
- Mold wax
- Clean rags
- Fiberglass mat
- Razor knife
- Gel coat
- Catalyst
- Gel coat spray gun
- Small buckets
- Stir sticks
- Fiberglass resin
- Felt roller
- Air roller
- 200 Grit sandpaper
- Small metal scraper
Instructions
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1
Prepare the keel mold by applying 2 to 3 coats of mold wax and let it dry. Wipe the excess away with a clean rag.
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2
Cut the mat so it completely covers the mold with no overlaps using a razor knife. You will have to cut the layer in pieces in order to cover the entire mold. Use the first layer as a pattern and cut 5 more layers of mat.
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3
Mix the gel coat with the catalyst in a small bucket, using a stir stick to mix it. Follow the directions on the containers for the correct amount of catalyst to add to the gel coat. Add the gel coat to the spray gun.
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4
Spray a first coat of gel coat onto the mold in a heavy mist, avoiding any runs in the paint. Let the first coat begin to get tacky and apply a second heavier coat, solidly covering the entire surface of the mold. Let the gel coat completely harden.
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5
Mix the fiberglass resin with the catalyst in a small bucket, using a stir stick to mix it. Wet out the entire surface of the gel coated mold with a 4-inch felt roller. Apply the first complete layer of mat and saturate the mat with resin mixture using the felt roller. Remove all the air bubbles that are trapped under the mat and flatten the mat out using an air roller. Continue this same process for each layer until all the mat is applied to the mold. Let the fiberglass harden.
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6
Slowly pry the keel from the mold using a small metal scraper. Pull the keel free from the mold and sand any rough fiberglass smooth using 200 grit sandpaper.
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Tips & Warnings
When working with fiberglass you should always work in well ventilated areas.
