MM Plaster
Gypsum Plaster is a material produced by partial or complete dehydration of mineral gypsum, usually with the addition of special retarders or hardeners.
It is applied to the surface in a plastic state (with water) where it sets and hardens by chemically reforming the gypsum with the water. It can be applied to brick, block or concrete surfaces to create a smooth surface.
The main ingredient of all gypsum plasters is gypsum rock—hydrous calcium sulfate—which contains about 20% water in the chemical composition. During processing, 3/4 of the gypsum is removed from the rock in this chemically mixed water using a controlled heating process called calcination.
When water is added during use, the material sets and hardens, returning to its original chemical composition.
By drying some of the chemically mixed water from the gypsum rock, it is converted into gypsum plaster.
First, the gypsum rock is ground and crushed in a mill to start the process. The gypsum is then heated on a flat metal plate above a kiln. If gypsum is heated at 120°C for one hour, hemihydrate (CaSO4.1⁄2H2O) – three-quarters of the water is removed.
This gypsum is known as Hemihydrates Plaster of Paris.
