Annealing, the controlled cooling of a glass, is critical to its longevity. Glasses which are not properly annealed will contain stress which may result in breakage before or at any time subsequent to their removal from the kiln.

The following chart represents a simple schedule used routinely in Bullseye's factory studio. Annealing schedules for thicker pieces (up to 8") are available from the factory upon request.
 
 

ANNEALING A TYPICAL (12" DIAMETER) BULLSEYE GLASS PROJECT
Thickness (inches)	Anneal Soak @ 960 ° F (In Minutes)	Anneal Cooling Rate 960-750° F (°F/HR)	Actual Time In Range 960-750 ° F	Cooling Rate* 750 ° F To Room Temp (°F/HR)	Actual Time* In Range (750°F To Room Temp)
1/8"	15 min	420	30 min	1013	40 min
3/16"	23 min	280	45 min	675	60 min
1/4"	30 min	210	60 min	500	80 min
3/8"	45 min	140	90 min	335	120 min

*Most kilns will not cool this rapidly due to residual heat in the refractories. Allowing the kiln to cool at its own rate between 750 ° F and room temperature is usually adequate for the final cooling stage. This may result in an actual cooling rate slower than that shown above. Cooling the work by opening the kiln door or large vent hole, however, risks thermal shock.