DIY Styrofoam Mold

You can use high density styrofoam to make a mold of a person's head.

Styrofoam isn't just the stuff you see wrapping packages and fast food. Styrofoam comes in many different qualities. You can buy high grade, high density styrofoam from art supply stores. This styrofoam can be cut, burned and sanded into shape. It is strong enough to serve as a mold for concrete and to be used as an external mold for robots.

Things You'll Need

• Sketch paper
• High Density Styrofoam
• Carving knife
• Hacksaw
• Floral Knife
• Hot-wire cutter

Instructions

1. Draw multiple sketches of your three-dimensional mold from many different angles. Draw the sketches full scale if possible. Get a read on the size of your mold.

2. Purchase an appropriately sized high density block of styrofoam from an art supply store. For large scale projects, you may want to purchase a hot-wire cutter from a hardware store. The wire heats up and cuts through the styrofoam easily.

3. Take a pencil and lightly sketch the outline of your mold on all sides of the block. Shade different areas of the sketch as a topographical guide.

4. Use a sharp knife, hacksaw, or hot-wire cutter to cut into the styrofoam. You want the blade to be as sharp as possible so change the blades every eight cuts or so. It is a good idea to wax the edges of your knife before every cut.

5. Cut off small chunks at a time. Leave about 5/8-inch of styrofoam off of your mold so you can sand in the details.

6. Use coarse sandpaper to get the final shape of your mold, then use fine grain sandpaper for a polished finish. You can paint onto your styrofoam mold with acrylic and glue styrofoam pieces together with a low temperature glue gun.

Tips & Warnings

• You can make a negative-space cast mold with high density styrofoam. Cut the block in half. Hollow out the image in negative space; halve of the image into each block like the mold's been cut in half. Pour a hardening agent into the cast and seal with tape or hand clamps. Split the mold when dry.

References

• Society of Robots: Materials -- Styrofoam
• Best Mix Mold Mix: Master Mold Materials
• Merchant Circle: How to Make Concrete Dog Bowls