Lots of different materials are used fr running out moulds.
The plaster used has three different names; casting plaster, plaster of paris and hemi-hydrate plaster. It comes in three types; fine, super fine and coarse.
Fine casting plaster is used the most out of all of the fibrous plasters and is also used in fixing and mitring.
Super fine plaster is used for work that needs detail in it such as mouldings. It can also be used to when casting along with fine plaster.
Coarse plaster can not be used for detailed work. It is mainly used for a thicker, bigger structure. It is also a lot cheaper.