Making molds for fiberglass with cheap gypsum

While fiberglass is used frequently as a material for molding, it can also be used for molds. The fiberglass molds are best for complex projects may need to be made ‚Äč‚Äčagain and again, because fiberglass is well maintained over time. The materials are also relatively inexpensive compared with other materials to molds. To make a two-part mold fiberglass that is suitable for molding plaster, follow these instructions.


Find a warm object which want to make copies. You can also make your own using foam or balsa wood and finish the outside smoothly. Determine the midline of the object from one side of the base to the other, and build a wall of modeling clay or place a partition table in modeling clay, so that you can maintain two mold halves separately. Make sure you have a smooth and small union as possible.

Apply several layers of wax molds to release the entire object, spreading the wax to make it as smooth and free of bubbles as possible. In the portion of the wax mold release liquid applying a layer of mold release agent. Let the mold dry and release when is specified in the product package.

Mix a small batch of resin, gel coat mold surface, fast hardener, silica filler and graphite powder all together following the instructions on the package. Working from one side project swabbed this thin layer of resin mixture to the edges of the hardened object starting from the corners. Allow the resin to dry and then apply a layer of gel over the rest of the warm object as a base. Let this layer to sit for half an hour.

Another batch of resin mixture and a thick layer should be applied over the gel layer. For this you must put wet resin in small strips of glass fiber cloth, letting the cloth soak resin. Let this coat dry for half an hour. Continue applying layers of resin and fiberglass cloth until you have a good thickness, and then let the fiberglass resin dry overnight.

Remove the modeling clay wall and clean the entire clay mold. If desired, you can cut marks on the edges of the mold halves fiberglass so that fit more closely with each other when you start using the mold. Repeat Steps 3-5 for the other side of the object tempered until the first half of the mold.

Cut the rough edges of the mold and separate the two halves. Prepare the mold for use with gypsum placing a layer of mold release agent.

Tips & Warnings

The resin is extremely toxic and should never touch the skin. Follow all safety precautions specified on the package.