GYPSUM AND MOLDS
Other than being inexpensive, gypsum is a high-filler and, when the drying cycle is complete, a minimum-shrinkage material. However, its low adhesive properties when applied to an original support make its use for reproducing small parts difficult. The mixture of gypsum and water used for molds initially creates, by reaction, a dense composite that becomes then solid and resistant. The high-hygroscopic behaviour makes gypsum the most commonly used material for the preparation of molds to cast liquid preparations that, when adhering, solidify in a short timeframe. However, there are additives that can alter the natural hardening process of gypsum by modifying the setting time (accelerants, retarders, fluidifiers, etc.) and its characteristics (reinforcement fibers, aggregates, etc.).
For the preparation of “negative” molds, PHASE offers a wide line of silicone rubbers selected among the best on the market, recommended for casting molds and copies of objects, sculptures and architectural elements.