A bronze bell consists of an alloy of 78% copper and 22% tin. In the Middle Ages, silver coins were thrown into it to give it a silvery sound. At Cornille-Havard, it is melted at 2 192 °F (1,200°C) in an oven dating from 1865. A channel allows filling the molds, which have been placed upside down since 2003. The cooling period lasts at least a week, depending on the size of the bell. The charred mold is then shattered, and the bell appears gray and black. It is polished and goes to the tuner who may remove some metal until obtaining the desired sound.