Fire couldn’t melt iron-hard metal, because fire relied on the chemical rusting of fuel.
“Chemical burning has a total heat-powered ceiling,” Giles Croft explained to Master Borin Bronze-Lung as they stood inside the newly hollowed underground spark vault at Depth Three Thousand.
“Burning carbon with sky air peaks at two thousand degrees. You can blow all the air you want. But you can’t beat the laws of heat laws.”
“Then how do we melt it?” Borin demanded, his hands stained with foundry soot. “If the ancient kings melted it, they must have used dragons or heavenly lightning.”
“They used high-hum alternating spark current,” Giles said, unrolling his newest blueprint across a wooden cable reel. “We don’t need fire. We need magnetic power-coil.”
On the blueprint was a rig that looked nothing like a traditional blast fire.
There was no stone chimney. There was no hearth, no charcoal hopper, and no blast tuyeres.
Instead, Giles had designed an eight-foot tube-shaped vessel built of ultra-pure zirconia baked-clay, capable of withstanding heat levels exceeding four thousand degrees. Wound tightly around the outside of the baked-clay crucible was a spiral coil of heavy, hollow copper tubing.
