How to Mold with Fiberglass Resin

What You'll Need
Mold release agent
Laminating fiberglass resin
Masking Tape

Fiberglass resin is a highly toxic material. Fiberglass is used in the auto industry, but artists and decorators are now using fiberglass resin for molding sculptures and other art objects. A two-part plaster mold is the most durable and effective way to mold hard fiberglass. It separates from the mold and does not get stuck.

Step 1: Avoid Injury

Wear a mask, suit and gloves to avoid getting the fiberglass resin on your clothes the first time that you attempt to mold with this toxic substance. You may even need a ventilation system to avoid inhaling fumes. If you are unlucky and get the fiberglass resin on your skin, you will feel itchy. Do not scratch. Wash the fiberglass resin away instead of scratching. Also protect the working area so that there is no mess that cannot be cleaned.

Step 2: Protect the Sculpture

Use a mold release agent to coat the sculpture. There are many types of mold release agents for different surfaces with varying ingredients.

Step 3: Add Gypsum

Construct a line of modeling clay up the middle of the sculpture and add the mixture of gypsum and water. It is best to add the gypsum to the water until the water becomes a creamy plaster texture in the bucket. Pick one half of the object, and apply the plaster mix with a paintbrush or gloved hands to form an impression coat. Wait 6 hours, and then add another coat of plaster and a layer of burlap strips. Repeat this process until a thick mold has formed. Repeat the entire process on the other side.

Step 4: Tear it Apart

Separate the clay modeling wall when you pull the plaster mold off of the sculpture. Make sure that the inner part of the mold does not have any clay residue on it. Dust the mold, paint it and coat with polyvinyl alcohol. Your mask should be on at this time.

Step 5: Set the Fiberglass Resin

Mix tiny amounts of laminating fiberglass resin and catalyst to paint an impression coat of the mixture on the interior of the mold. Fiberglass cloth should be cut and placed in the mold halves and coated with laminating resin. This process is repeated until the mold is thick. Wait again until the fiberglass resin casting can be carefully separated from the mold. Drop it into the mold to finish curing.

Step 6: Add Finishing Touches

Cut leftover fiberglass, and align the halves of the casting. Hopefully, they match. Use masking tape to join them, seal the seam with more resin and fiberglass. Then take the masking tape off gently. Sand down the seam and you have made your own artwork from fiberglass resin that you can be proud of.

Although the task is time-consuming and the material can be hazardous, many artists get used to this process and they know that practice makes the object perfect. Keep concentrating, and always wear protective clothing.