I shed my winter layers quickly. After a careful explanation of the procedures, she hands me a thick silvery apron and what looks like a welder's mask. Next, she gives me a pair of heavy canvas-covered gloves that smell like sweaty gym mats. Barnes wrinkles her nose in sympathy. She points to the glass beaker resting on the black counter.
Barnes opens the furnace door.
The inside glows a deep reddish-orange. I slowly tap the gray powder on top of the molten batch already in the crucible. The liquid sucks in the powder, and burps out small gas bubbles. What you just did is called charging the batch. A few minutes later, we charge the batch again.