The basic Caldera is part of a kiln expansion system. When you are ready to anneal glass beads, add the modular Caldera-BC collar. It is a kiln section that stacks onto the main Caldera or Caldera-S kiln base. The Caldera-BC collar has a 6 ½” x 2” door on the side for annealing glass beads. The collar includes a brushed stainless steel mandrel holder. Insert the mandrels into the kiln. The bead door stays partially open while the glass anneals. The kiln ships with a rare earth magnet to hold the bead door open.
The Caldera-BC collar adds 4 ½” of height to the main kiln. The collar has no heating elements. The Caldera and Caldera-S, with a collar, still fire to 2000°F/1093°C. The Collar is made of 2 ½” hand-selected insulating refractory firebricks. The insulating firebricks, wrapped in heavy-gauge stainless steel, soak up heat for slow, efficient cooling.