So is wax pouring, wax chasing, bronze chasing and patina work. That's five different specialties right there. The wax is burned out of the investment, so the investment has to hold up to the bronze pour or the week or more of preparation in creating that investment is lost. Investments do blow out from time to time, with molten bronze running out everywhere, which is why foundry workers wear Kevlar suits to protect them. The artist may take anywhere from a month to 4 or 5 months to create an original work of table-sized art.
Monumental work can take up to a year sometimes.
If the mold-maker, wax chaser, bronze chaser or any of the others who work in this process don't do their jobs well, the entire original may be lost, with no reproduction possible. When you see a bronze that's beautiful in every way, it's the product of not only the artist, but of many talented artisans at the foundry, the skill of the basemaker and the marble supplier. These sculptures are usually foundry-cast, produced in a pressure tank, as are their molds. The molds are silicon rubber with plaster mother molds. The pressure tank is also used when casting the sculptures to get bubbles out of the finished sculpture and to be certain the casting material gets into every part of the mold.