Tom Wartman is standing over a rectangle of blue flame and bending glass in his hands. "This fire is about 1,500 degrees," he says casually. He quickly and deftly moves the glass arc from the flame to ...

In a cluttered corner of his New Orleans studio, Nate Sheaffer pulled a glass tube through blue flames, coaxing it with gentle puffs from a blow hose until it curled into cursive letters. Four mounted ...