The thick section went on the fixture first.
Tavin heated it. The well’s old furnace stood at the chamber’s edge beside the bench: a brick hearth with an iron door and a single damper, built for the Founders’ teams, much larger than they needed. He opened the door with the key and laid the thick section in on the tongs and closed the door and watched the furnace’s small glass port.
One run. Up to the quench temperature in one long heat.
When he drew it out, it glowed. Mara watched it on the tongs in the chamber’s dim light. The edges bright, almost yellow. The center dark. A deep dull red, much darker than the edges, like a coal with ash on it.
“It’s holding the wrong heat in the middle,” Tavin said.
He said it plainly, neither pleased nor conceding. A reading.
He set the section on the fixture and read the thermal gauge clipped to it: the edge temperature, the center temperature. He wrote the difference on the slate, in the column under THICK, cycle one.
Mara read the figure. It was larger than she had thought it would be. The thick section had come out of the furnace looking finished, glowing, solid. And inside it, the heat had pooled in the middle like water in a basin, and the edges had already started to cool around it.
