Plaster is produced through the burning process that applies pressure and heat to gypsum.
Plasters are divided into alpha and beta type , and alpha - CaSO4-1 / 2H20 ( alpha - hemihydrate gypsum ) is manufactured by wet manufacturing method and pressure vapor method and pressure solution eclectic method are also used for manufacturing BETA - CaSO4-1 / 2H20 ( beta - hemihydrate gypsum ) is manufactured by normal pressure calcine which is the dry manufacturing method .