To use plastic molds for plaster, first cover your work station with a protective covering, such as plastic or newspaper and clean the molds, making sure there is no residue or debris. Dry the mold thoroughly because any excess water lengthens the setting time of plaster.Continue Reading
Mix the plaster appropriately before pouring the mixture into the mold. Cold water makes the plaster easy to manipulate during the molding stage, and the proper plaster thickness keeps the final product from being powdery or misshapen. Pour the mixture slowly into the mold, and ensure all the parts of the mold are filled to capture the exact detail of the mold. Once the mold is filled, softly tap the mold against a solid surface to release air bubbles in the mixture.
Allow the mixture to dry an appropriate amount of time relative to the size of the mold. Carefully loosen the outer edges of the plaster from the mold, and slowly remove the finished product. Don't shake or force it out of the mold. If the mold is shaped appropriately, carefully twist the mold to release any sections that are stuck. Some plastic molds are made to peel away from the finished plaster.Learn more about Building Materials