A cycle of service for a cupola in active use is usually repeated each 24 hours. Briefly the operation throughout the 24 hours is as follows: A day's melting having been finished, and the blower stopped, all metal and slag are drained out at the tapping hole. The prop is knocked away, and the doors FF swing down. The sand bottom and any unburnt fuel drop out.

Next morning the cupola is cool and the melter and his helper proceed to prepare it for use. Slag is chipped from the lining, which is patched where needed with plastic fire clay. Old sand is dug from the doors, breast and tapping spout. The doors are then propped up and the melter goes down through the charging door to prepare a new bottom. This is made about 4 inches thick, and consists of a thin layer of cinder, a layer of new moulding sand and a coating of thick clay wash. The sand bottom continues out to the end of the tapping spout.

After the bottom has dried about an hour, a wood fire is built in the cupola. The breast is rammed with new sand around an iron pipe, and the pipe is then withdrawn to form the tapping hole.

Coke and iron are weighed out for the charge and are hoisted to the charging platform. A hot coke fire is gradually built up, the blower is started, and the charging begins. The charge consists of alternate layers of coke and iron, and each layer must be weighed to make the operation of the cupola uniform and to insure enough coke to melt the iron. Pig and scrap iron are charged together. Molten metal appears at the tapping hole about half an hour after iron is charged, and this hole is stopped with a clay plug jammed into place on the end of a heavy round stick.

In the meantime, the foundrymen are-assembling the ladles to be used in pouring the moulds. A wood fire is built in each ladle to keep it from chilling the molten metal it receives. When enough molten metal accumulates in the cupola, the clay plug is dug out with an iron bar, ladles are filled, and the tapping hole is again stopped.

Charging continues from the upper platform so long as metal is needed, and when all moulds are poured, the remaining iron is run from the cupola and the blower is stopped.