Alginate is a special type of algae used to make molds – sounds gross, but I assure you you’ve seen it, touched it, and probably had it in your mouth before! Dentists use it to make molds of your teeth when they give you braces and retainers. Once the alginate is mixed with water (1:1 ratio), you pour it over whatever you want to take a mold of and wait for it to set up. It sets to a rubbery consistency, which is perfect for capturing details in hands and feet. For these molds, we were able to pull the feet out of the alginate with little or no tearing.

We had to layer the bottom of the plastic containers with clay (when we were making the alginate molds) so the plastic wouldn’t melt when we poured wax into the alginate mold. Hot wax is poured into the alginate molds to cast a positive replica of the foot; those wax feet can then be used to make plaster molds for press-molding.