It worked! Aluminum Session No.6
Finally, March 9, a few days before the Covid shutdown, we got ourselves some half-decent aluminum castings! This time, for the molds, we remembered to mix the plaster with sand and added vents, even if perhaps the patterns didn't need them. We didn't design the molds to have the metal melt directly in a basin though; we went with our traditional casting-from-a-tin-can method instead. The kiln was quite stacked with four molds, bricks to deflect the flame, and the crucible-soup can with the aluminum. We started low and went nice and slow in order to melt out the residual wax. Around 300° C you could smell a faint wax smell, so this was a good sign. (Another good sign was the garage smoke detector going off; at least we know that works well.) (I opened the garage door a bit more afterwards.) We stayed stable around 400° C by the first hour or so, and then increased to 500° over the next hour, and then reached 600° the following hour. By this time a crack ...