If you have a part that you use often or replace every once in awhile, it could be worth your while to create a fiberglass mold. These molds are often used to make copies of automotive parts or hobby items. Once you have created your mold, it can be used for years to come to create identical products. You can find all the items you need to create your own fiberglass mold at your local hardware store or online.
Instructions
1. Take the "plug," or the shape you wish to duplicate, and make sure its surface looks smooth and perfect so that no imperfections appear in the product.
2. Apply a coating of wax release agent to the plug with a cloth. Wait a few minutes for the wax to harden then buff the surface to a shine with a clean cloth. Repeat this process at least five times, leaving several hours between coats. The wax layers will fill any small imperfections in the plug surface.
3. Coat the plug with PVA, a plastic green-colored liquid film that will prevent the mold from sticking to the plug. Spray on three thin coats with a spray gun. You must wait a half hour between each coat to allow the PVA to dry.
4. Catalyze the wax-free gelcoat by adding MEK peroxide hardener according to the package instructions. Combine the ingredients in a small bucket and then mix with a stir stick.
5. Add a layer of gelcoat evenly at a distance of 6 to 12 inches with a spray gun that has air pressure of about 85 pounds. This gelcoat will serve as the mold's surface. Apply two coats, waiting several hours between coats. Leave the gelcoat layers to set from two hours to overnight.
6. Add MEK peroxide to a small bucket of resin following the package instructions to catalyze the resin. Mix them with a stir stick. Tear out strips of chopped strand fiberglass mat with your hands.
7. Apply a layer of the resin mixture onto the plug with a brush. Layer strips of fiberglass cloth over the wet resin. Paint a second coat of resin over the fiberglass cloth pieces. Remove any air bubbles from underneath the layer using an air roller. Apply additional layers, alternating resin and fiberglass cloth strips, building up the mold to the desired thickness. Leave the mold to set for several days.
8. Trim any excess material to the mold edge using a saber saw. Sand the edges of the mold carefully with sandpaper until the line between the mold and plug is exposed. Insert a sharpened wooden stick into this exposed line. Carefully move it around the mold to separate the edges.
9. Pull the plug free. Sand the mold surface until smooth with sandpaper, then add a fiberglass finish compound to the mold surface.
