What are gypsum, silicone, latex, alginate, and polysulfide molds?
Gypsum is a fine-grained cement (much like a strong plaster) while silicone, latex, alginate and polysulfide molds are elastomers (flexible mold materials) which are utilized to duplicate everything from sculpture to fossils. Gypsum is inflexible and may generally be used only to produce multiple-piece molds of simple objects, while silicones and polysulfides are synthetic materials and highly elastic (which can tolerate resins and waxes). Latex is derived from natural sources and alginates are kelp-based, short-lived, and generally relegated for casting cements (they are most commonly used in molding body parts — life masks, dental impressions, etc).
