Things You'll Need
Mold release agent
Plastic trash bags
Fiberglass resin and catalyst
Sandpaper or electric sander
Fiberglass, a typical material for creating tough plastic objects, is most often shaped and manipulated using a mold, or negative design depression. However, using a negative mold is not the only way to shape fiberglass. In order to create large fiberglass pieces or sculptures, positive molds are often the best option. This type of mold may be made from simple chicken wire or wood, and is built with the design details on the outside, so that the fiberglass can be draped over it.
Create your desired shape out of chicken wire, bending the wire and securing it in place so that it does not move during the fiberglass casting process.
Cover the chicken wire with aluminum foil so that there are no gaps. Make sure that the foil does not make too many lumpy areas, or lumps that will be too big to sand down later.
Spray the entire chicken wire sculpture with a mold release agent, which will allow you to remove the fiberglass more easily later in the process. Allow the mold release agent to dry.
Move your sculpture into an airy, well-ventilated workspace. Cover all surfaces around and under the sculpture with plastic trash bags. Put on your latex gloves, vapor respirator and safety goggles.
Mix together a small amount of fiberglass resin in the paint tray, using the solution percentages that came with the product. Stir the bubbles out of the solution.
Cut your fiberglass mats into a manageable size for your chicken wire sculpture. Dip a mat into the resin solution so that it becomes completely wet.
Lay the wet fiberglass mat over your sculpture and press it into place, molding it to the shape of the chicken wire. Lay similar mats all over your sculpture until it is completely covered.
Let this layer of fiberglass dry for a few hours. Pull the hardened layer of fiberglass off the chicken wire and discard the original sculpture.
Mix together another tray of resin and lay down another layer of fiberglass mat. Make sure that the fiberglass sticks well to itself.
Let the fiberglass dry, then continue adding layers until you have the thickness you would like. Once finished with the layers, let the whole fiberglass cast dry overnight.
Clean up all spilled fiberglass resin with turpentine.
Put on your particle respirator and safety goggles. Sand down the surface of the fiberglass cast, removing lumps and sharp edges, using either traditional sandpaper or an electric sander.