A disturbing, yet beautiful piece. *Spider Goddess is also available in a display version, which is filled with a flexible foam to preserve its shape and structure. *. There are 2 basic ways to fill up a mould, depending on the quantity of foam you grams of latex base, whereas a full head mask of, say, a werewolf could take. Start filling the mold with latex. To get rid of all bubbles you might want to attach a chip brush, on an angle to a paint stick and going into the latex sitting in the. To make a part out of latex, you first must make a plaster mold from the original, which to be very thin, then you are nearly done—buy a water-based latex and fill the mold with it. This is how your standard Halloween mask is made. Then, using Urethane Elastomer Foam (the best supplier of this is Burman Foam in the.