Bronze Casting - Checking Temperature

Two workers are pouring the extra buckets of sand around the shells to hold them upright. The foil keeps dust from the inside of the shells. The foil is removed (of course) before the bronze is poured.

At this point the molds are still hot but have cooled a bit. When they first come out of the oven, they are so hot you can see black body radiation - which led to the discovery of quantum theory - from the inside of the shells. In other words, the inside of the shells glow a nice pretty orange.