What is plaster made of?
Traditional plaster is made of hydrated lime, sand, water, and horse hair (or some other type of hair) added for tensile strength. When mixed, traditional plaster has the consistency of runny peanut butter. As plaster sets, the lime within the plaster mix absorbs Carbon Dioxide and is essentially converted back into limestone, resulting in a hard and durable material. Plaster is usually applied in three coats: the scratch coat, brown coat, and finish coat, and is rather labor intensive.
