Stop Motion by Susannah Shaw. Reprinted with permission.

The Sculpt
If the puppet is to have a foam latex, or silicone covered body, you will need to first sculpt your model to make a mold to cast these materials in. This is called the sculpt or the maquette. You may also need to make some hard parts for your model: sometimes feet, or hair, or even faces may need to be hard. The general rule is: If you are casting a hard piece, you will need a soft mold (silicone) and if you’re making a soft piece, you’ll need a hard mold (plaster, resin or fiberglass).

Make your armature. You may want to make separate parts of the body that can join together. In this case it’s useful on the armature to glue (epoxy) brass sleeve tubing at these points (arms to hands, neck to head). It’s best to use a very firm clay for your maquette, as details and fine lines have to hold as it goes through the foaming or molding process. Blair Clark, visual effects supervisor at Tippett Studio prefers a Chavant clay. Mackinnon & Saunders in the U.K. use Harbutts, now made by Newclay Products. Others use Plastiline. Build up the clay and sculpt to the right shape.

Sculptor Stuart Sutcliffe, working at Mackinnon & Saunders, sets a mirror on the other side of the character he is sculpting, so that he can check the figure for symmetry. “When you look at things, you tend not to see any discrepancies, your eye gets used to it. But with a mirror, the image is reversed, it confuses your brain and you can suddenly see all the discrepancies: there’s a big lump on that side, or there’s a sharper curve there than the other side.”

Stuart Sutcliffe at work. Courtesy Mackinnon & Saunders. Photo © Susannah Shaw.

Textures
For textures such as wrinkly skin, dinosaur skin or fabric you can use ready-bought stamps from various sources or make your own taking latex casts off any surface: old leather, almond stones, bark, leaves, stone. To make good facial wrinkles on Plasticine, cover it first with cling wrap, then mark with a sharp edged tool, it just softens the sharp edges.

Undercuts
The presence of undercuts, i.e., a corner or curve that will be problematic when trying to release the mold, is probably one of the most important aspects of mold making. To assess how many pieces you will need for your mold you will need to look the model over very carefully to see if there is an undercut. Don’t rush this stage. You will need to work out whether you will need more than two divisions for the mold, and where those divisions should come.

Seams
You will also need to think carefully about where the joins come on your model. This is because when you first take your cast out of the mold, you will inevitably have excess foam or silicone around the join (flashlines), which will need to be cut or sanded away. It would be unfortunate to design your mold so that the seam comes over the face, or some other exposed area. The sides of the body are generally easier to clean up.

The different elements need to be worked out — the body might be cast in foam latex; the head and the hands might be cast in silicone, which means they’ll need separate molds. For maintenance purposes, if it’s a series, hands need recasting on a regular basis. Because the wires in the fingers are heavily used, they should have a separate mold so you don’t have to cast the whole body each time. The body should only need to be cast once — it should last for a whole series, especially if it’s got a costume over it.