Pit Moulding:

• It is used for very large casting work and done on the foundry floor.
• A pit dug in a floor act as a lower flask [drag] and top flask [cope] is placed over the pit.
• The walls of the pit are brick-lined and Plastered with loam sand and allowed to dry.
• Sometimes pit bottom is rammed with 50-80 mm layer of coke to improve permeability of mould.
• Vent pipes are run from this layer to the surface.
• Coke is covered with backing sand.