Q. Describe Dry and wet parting materials?

Dry parting materials: These are applied by dusting. These include : charcoal, ground bone and limestone, lycopodium(a yellow vegetable matter), tripolite(a silicate rock), ground nut shells, Talc(Magnesium silicate,3MgO,4SiO₂.H₂O)and Calcium phosphate.

Wet parting materials: These are not used with wooden patterns, but are used mostly in machine moulding when metal patterns are used. They are wax based preparation, petroleum jelly mixed with oil, paraffin and stearic acid.