A gypsum for casting commonly referred to as grilling or buried.
While 2.2 lbs (1 kg) of powder, it is mixed with 450 mL of water, professional use requires drying and firing for complete drainage.
The properties of this gypsum allow for easy casting.
Create a prototype with styrofoam or wood wax, and place it inside the hyston, and heat it at high temperatures (gas / electric kettle, electric furnace, burner, etc.), Styrorol and wax prototypes will burn out, volatilize and allow it to be hollow (female type).
Cast with a cast metal in it.
1 kg of slab is 3.5 inches (9 cm) per cube