About of Plaster of Paris.
The Egyptian & Greeks used Plaster of Paris for sculpting tombs & other monuments. In India POP was prepared by burning gypsum in open air fire, then crushing it & mixing it with water & using as joining material in forts.
Gypsum is a sedimentary rock. Selection of finest gypsum & the preparation methods are the primary factors that results into production of best plasters.
POP is basically a building material that consists of fine, white coloured powder known as hemi hydrate Calcium sulphate. POP is obtained by heating gypsum or dehydrate Calcium sulphate to about 140 to 1800C. When gypsum is heated to such temperature it loses three quarters of its water content leading to the formation of plaster of Paris.
The process of making POP is reversible; means that if dry plaster powder is mixed with water, it reforms into gypsum but the properties of gypsum are lost.
Why J.B. Plaster
J.B. Plaster is made from hemihydrate Calcium Sulphate to which no additives are added. It is manufactured in an automatic rotatory drum under controlled temperature.