When the water dries out, it hardens and helps keep the bandage in place.
This ensures that the fracture stays in place and the bone does not take any more damage due to movement.
It gains water and crystallises when water is added to the gypsum. It hardens and helps maintain the bandage in place when the water dries out. This guarantees the fracture remains in location and due to motion, the bone does not take any more harm.
Paris plaster is heated to 373 K by heating gypsum. Gypsum becomes powder after heating. When Paris plaster is applied to surgical bandages after wetting them, it gains its crystallisation water again and becomes difficult. So keep the fractured bone in location.
no need ! : )