Cast

How does plaster bind?
Gypsum is chemically bonded by attaching water. The water lost during firing combines with the gypsum again during its setting after adding mixing water.

Please explain, why gypsum is not suitable for external use
Gypsum also dissolves in water after it has set. In temperature 291 K (18°C) w 1 l of water dissolves 2,01 g of plaster.

Please list the types of construction plaster (wg DIN)*
The following types of construction plaster are distinguished: stucco plaster, plastering, for ready plaster, adhesive, for embedding, for grouting, putty and for mechanical plastering.

In Poland, The gypsum binder generally used is building gypsum, meeting the requirements of PN. It comes in two varieties: as full- and fine-grained (former model); Apart from building gypsum, a distinction is made between plaster and putty gypsum and gypsum glue.