Carol Anne Beckman - Annealing Schedule 2009
This schedule was provided by Carol Anne Beckman. I have added conversions to °C. In Carol's words:
"1. Ramp up as fast or as slow as you feel necessary to 980 degrees fahrenheit (527°C).
2. I do not have a separate temperature for soaking and annealing. I use 980 Degrees Fahrenheit (527°C) for soaking and annealing.
3. Your program should be as long as your working time, plus a minimum of 2 hours. The 2 hour time must be increased if your beads are bigger than 4 centimeters. The guideline that I learned is 1/2 hour annealing time for each centimeter of bead size with a minimum of 2 hours.
4. So, a bead that had a largest measurement of 6 centimeters would need to be annealed for 3 hours.
5. After the annealing segment of your annealing program, you want to take the kiln down to 800 degrees Fahrenheit (427°C) at a rate of between 60 degrees Fahrenheit to 100 degrees Fahrenheit per hour (33 to 56°C/hr). The range from 60 degrees to 100 degrees per hour (33 to 56°C/hr) is in case you included a bunch of strange stuff in your bead and you want to baby your bead during this part of the annealing cycle...
6. Then, your hold time at 800 degrees Fahrenheit (427°C) (step 5) is going to be the SAME as the amount of time you annealed your beads in step 3.
7. After holding, take your beads down to room temperature at a rate of 60 to 100 degrees fahrenheit per hour (33 to 56°C/hr), depending again on how much strange stuff you mixed in with your bead. For more strange stuff, slower."
Note: your kiln may run hotter than the temperature it displays, and may have a temperature gradient across it, with some areas warmer than others. If you are getting unexpected results, try checking the temperature inside the kiln with a separate thermocouple. Alternatively, do some runs with strategically-placed test beads, adjusting the temperature by 10 degrees each time until you get the desired result. If you use transparent glass you can check the beads for stress with a home-made polariscope.
Converting temperatures and ramps
Google will convert Fahrenheit to Celsius, but converting degrees per hour is a bit trickier. There is a handy tool by Brad Walker: Temperature and Rate Conversion at the Warm Glass tip archive that will also convert ramps in F to C for you.