I made alum. castings for company I once worked for. We had a small outdoor furnace that sounded like a jet engine when it was running.
My furnace sounds like a hair dryer. It's charcoal-fired, but isn't even distantly related to the small backyard charcoal barbeque. Some people see a bag of Kingsford [formerly Ford Motor Company] charcoal briquettes and think picnic; others see the same but think of the broken window crank handle in their '55 Chevy.
I am kind of wondering how they will achieve an intermediate temperature for casting this low-temperature alloy. It's too much for the kitchen stove, but the furnace is too much. Maybe a wood-fired ceramics kiln.