The silver is melted with an acetylene torch to cherry red liquid. The baked out mold, at about 1000 degrees F, is immediately set onto the cradle at the end of the centrifuge arm. My heart is pounding with anticipation of the critical moment. I release the centrifuge and duck for cover. The centrifuge springs to action throwing the molten silver from the crucible into the channel in the mold left by the wax sprue trunk.
Molten silver flows down into the cavities left by the wax objects inside the mold.
Some molten silver misses the mold, flies out of the centrifuge enclosure, slips past the collar of my shirt and sizzles across my back. The whirling centrifuge slowly comes to a stop. I toss the hot mold filled with silver into a tub of water. The water boils violently as the investment shatters and crumbles to release a silver replica of the wax sprue and original wax objects. The silver objects are cut from the silver sprue trunk with a jeweler's saw.