Plaster of Paris and most casting plasters are great for casting toy dinosaurs, handprints and crafts at home and school for your kids, but the professional conservator needs a much higher quality product. You will find that most casting materials mix at a ratio of upwards to 100 parts water to 100 parts plaster. This can cause any number of problems when crafting larger casts. Due to the extra water, longer drying times are needed and the finished cast will have at best, half its potential strength. If dried to quickly, the cast can easily warp, distort and or generate stress cracks that will sooner or later cause the cast to fail.
Listed below you will find several casting media that we have selected to offer conservators. These products are specifically designed to eliminate many problems that can arise from casting small losses to the largest of reproductions.
Polyfilla Patching Plaster is a cellulose fiber reinforced plaster. Polyfilla is a medium for sculpturing, modeling and relief work. It easily mixes with water to provide a white, non-shrinking, slow setting filler which sands easily when set. The mixing ratio is 1 part water to 2 parts Polyfilla. Two pounds of Polyfilla will make approx. 1 quart of mix. Always add dry Polyfilla to the water, not the other way around. Working time is 40-60 minutes. Set time is 70-120 minutes.