How to Use the Fiberglass Spray Lay-up Process
When building something using fiberglass, you can apply the fiberglass in two different ways. Many people are familiar with the hand lay-up process, in which you put a piece of fiberglass over a mold, then use a paint brush to cover it with resin. The second, less commonly known, option is spray lay-up. In this method of construction, you use a spray gun that mixes the resin and the fiberglass to cover a mold. This is more commonly used in larger molds where precision doesn't matter. Does this Spark an idea?
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Things You'll Need
- Mold release agent
- Sprayer
- Paint brush
- Gel coat
- Felt roller
- Barrier coat
- Epoxy
- Drill mixer
- Resin mixture
- Glass fiber rovings
- Fiberglass sprayer
Instructions
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1
Apply a mold release agent to the mold. This can be done by using a sprayer or a brush. Apply two to four coats of release agent.
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2
Apply a gel coat to the surface of the mold. Again, this can be sprayed on or brushed on. Either way, it's important to have an even finish. Give the gel coat four hours to harden before moving on to the next step.
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3
Apply a barrier coat. Mix the epoxy with a drill mixer, let it sit for 15 minutes, then use a felt roller to apply the barrier coat. Let the barrier coat sit for three hours, then apply a second coat. The barrier coat protects against water damage.
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4
Mix the resin according to manufacturer's instructions. Pour it into the holding tank of the fiberglass sprayer. Insert the glass fiber rovings into their designated area of the spray gun.
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5
Spray the mold. The resin will mix with the chopped fiberglass as it hits the mold. Move the spray gun in a predetermined pattern to make sure you get an even coat.
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6
Use a roller on the mold once the mixture has been sprayed. This ensures the resin and the fiberglass bits are stuck together and that entrapped air is removed.
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7
Allow the fiberglass to cure for a few hours. Repeat steps 5 and 6. Allow the glass to cure again.
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8
Remove the fiberglass from the mold. If you applied the mold release agent properly, this should be relatively easy.
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Tips & Warnings
Always wear safety goggles and a ventilation mask when working with fiberglass.
