ABSTRACT
A prop builder makes a mold when they want multiple copies of an object. Molding and casting allows an artisan to create a replica of something that cannot be used as a prop. A mold can be either flexible or rigid. Prop builders commonly use silicone rubber for flexible molds and plaster for rigid ones. Air bubbles can be present in the casting material itself, which may be too viscous or solidify too quickly for the bubbles to rise to the top. A box mold is where prop builders build a box or some other wall around an object and fill it with their molding material. A one-piece box mold is one of the simplest to make. A waste mold needs to be destroyed to remove or release the positive cast inside. It is less time-consuming to make and it eliminates seam lines, but it can only be used once.
