Things You'll Need
Clear coating gel
Resin and fiberglass often work well together in projects that require a mold, such as making dolls, toys, models, automotive bodies and other plastic items. Layering resin and fiberglass inside the mold allows all the layers to harden together into a durable plastic when dry. Although you can buy the top layer of resin, called the gel coat, in many different colors to create colored plastic, some hobbyists prefer to mix their own colors to make unusual shades.
Wearing a vapor respirator to avoid inhaling the toxic resin fumes, set up your work area in a well-ventilated room. Spray or coat the inside of your project's mold with a mold release agent, and put on a pair of latex gloves.
Mix together your gel-coat resin with its catalyst, following the instructions for the particular brand you bought. Stir the mixture until you have eliminated most of the air bubbles.
Add your resin color pigment to the mixture, blending it in well. You can also shave or crush arist's pastels to create pigment instead of buying a particular type. Make sure you've created a consistent color throughout the gel-coat resin.
Paint an impression coat on the inside of the mold with the gel-coat resin, getting into all the crevices and corners. Let the impression coat cure for 30 minutes, then add another coat of the colored resin. Continue adding layers of resin until you have built up the outer thickness that you want.
Cut your fiberglass cloth into small strips. Mix together your regular polyester resin with its catalyst, following the instructions for the brand you have. Stir the mixture well.
Paint over the gel coat resin with a layer of regular resin. Press pieces of fiberglass into this layer, letting the cloth soak up the resin. Paint another layer of resin over the fiberglass cloth.
Continue layering fiberglass cloth and resin until you have the thickness you want. Let the resin cure for a few hours, then remove your fiberglass design from the mold to break the seal. Place the design back into the mold to continue curing for another day.
Do not touch the resin, as it is highly toxic and can irritate your skin.