Some people believe that a sculptor “works in bronze”—that just as he chips and polishes a block of stone to create a marble statue, he somehow hammers and twists and welds metal to produce a bronze statue. Not so. A bronze statue is only a reproduction of some figure he has made in another material. It is as hollow as a bell and is made in the same way: by filling a mold with liquid metal.
Casting, as the making of that bell/statue is called, is a technical affair in which at least four or five different specialists take part: and most sculptors usually leave it all up to them—they doesn’t even watch while their bronze statue is being made.
If you’ve read Benvenuto Cellini’s autobiography you will remember how complex and exciting the casting of his big bronze Perseus was; things went wrong at the critical moment and he almost lost the statue. And earlier in the book, when he wrote of his stay in France, he tells how the French foundrymen ruined a bronze of his through incompetence. Michelangelo had to model his twelve-foot statue of Pope Julius a second time because the foundry technicians botched the first version. It was and still is a very complex thing to cast a figure in bronze, even a small one; and the sculptor, though he must know how to work in many materials and with all kinds of instruments, has traditionally drawn the line here. He takes his plaster model to the foundry and turns it over to the specialists. He gives a few orders about the base it is to have (wood or marble) and the color of the patina, and goes home until they call him to come and pick it up.