With a two-part plaster mold, you can create a negative 3-D cast, or a hollow mold, of almost any object and recast that object in a variety of materials. Plaster molds work particularly well for casting latex and wax, but you can also use them for fiberglass and resin with the right release agent. With proper technique and plenty of petroleum jelly, you can pull many copies of the cast object from a single mold. Two-part plaster molds are inexpensive to make and set up very quickly.
Instructions
1. Locate the center line halfway between the front and back of the object of which you are making a mold. This is important for creating a strong mold with two halves equal in size.
2. Build a 2-inch thick slab out of water-based clay to shore up your model. Lay the model on the slab of clay, and use more clay to build a 2-inch thick retaining wall at the dividing line. A retaining wall is a barrier that keeps the wet plaster contained. The goal is to expose the front half of the object you are casting, as you will build your mold one half at a time.
3. Scoop out a circular section of clay in all four corners of the retaining wall with a penny. You are creating registration points that will ultimately help the two halves of your mold align.
4. Create a box around the clay slab with four sections of 2-by-4-inch board. The clay slab should be 2 by 4 inches. Secure the boards tightly around the clay base with clamps. Do not nail the boards together; you will remove the clamps and reuse the boards later.
5. Cover the model, the clay and the insides of the boards with a thick coat of petroleum jelly to help the pieces release.
6. Mix up a bucket of plaster of Paris per the package directions. Tap the bucket against the floor or table edge to remove all bubbles, then pour the plaster until it is level with the tops of the boards. Allow 15 to 30 minutes for the plaster to set. It will get very warm and then gradually cool down as it hardens.
7. Remove the boards and clay from around the model. Flip the model and mold upside down, holding them together. The model is now facing up.
8. Apply more petroleum jelly to the backside of the mold you just cast and to the boards. Reset the boards, and clamp them around the first half of your mold.
9. Mix another bucket of plaster, and pour it over the back of your model, up to the edge of the boards. When it sets, remove the boards and gently pry the two halves of your mold apart. Allow them to dry overnight before attempting to use them for casting.
Related posts
You can easily make a nontoxic plaster mold in a home workshop or studio.Plaster is an excellent material for sculpture, crafting and mold-making. It is easy to work with, it dries quickly and, us...
Plaster molds are a handy tool in mass producing ceramics.Plaster molds are used when you want to produce numerous castings of a single object when crafting ceramics. A mold, depending on the obje...
Molds for many plaster crafts can be made from molding clay or carved into pieces of wood. Clay is best used when only a portion of an object is going to be replicated with plaster, simply by pres...
Plaster molds help increase the output of your ceramics studio.Ceramicists know that clay molds made from CastRite plaster of Paris are among the very best in the world. CastRite's gypsum-based fo...
Gather Materials and Prepare PartitionTo create a simple plaster mold, you will need the object to be molded; clay; two disposable containers; Vaseline, mold release or orange shellac; plaster; wa...
