Proper moulding appliances are necessary for making the cup leathers of ordinary force and lift pumps. The iron or gun-metal moulds are the shape and size of the outside, and the stamp or core is of the size of the inside of the cup leather. The leather is cut circular and then soaked for a few hours in water or oil, accordingly as it is dressed or prepared, and then pressed into the mould by the stamp with considerable force. Temporary moulds and stamps can be made by turning them out of solid blocks of very hard wood, a lever being used for pressing one into the other, with the leather between them.