Hello, and thanks for the invite! My name is Joe Lester and I'm the Chicago area.
I've been asked to show a picture....lets see if this works:
I sculpted it out of a water based ceramic clay called Michigan White. I sculpted it over a lifecast of a person, and its larger than life size. This is because the final mask will be latex, and latex always shrinks a certain percentage.
I waited until the sculpt had become firm to make the moldmaking easier. I made the mold out of Ultracal 30, in two parts, with the dividing line down the sides and around the ears. Undercuts weren't a problem because the clay was easily dug out of the finished mold. The teeth were the only part I had to pay a lot of attention to while sculpting to make sure they didn't have undercuts behind them at all.
The final item was made into a latex mask by the absorbtion method, just like with ceramics. You pour in the latex, wait a while, and pour it out, and it forms a skin inside. When dry, this is pealed out, and that is the finished mask, ready to be trimmed and painted.