If you are not using a kiln vent, leave peephole plugs out and vent the lid. Set the alarm to 1000°F. When the alarm sounds, close the lid from venting position.
Set the alarm again, this time to 1850° F. When it sounds, check the witness cone through the peephole. When the cone bends to six o’clock, write down the temperature. (Use that temperature in segment 4 on your next firing of the same type of ware.) Then press 9, ENTER(Skip Segment).
This will advance you to segment 5, a slow cooling seg- ment. Do not open the lid until the kiln has cooled to room temperature.
Glass Fusing Firing Schedule
| Rate | Temp. |
|
Segment | °F/°C | °F/°C | Hold |
1 | 250/138 | 750/398 | 00.00 |
2 | 900/500 | 1425/773 | 00.30 |
3 | 9999/9999 | 1050/565 | 00.00 |
4 | 150/83 | 750/398 | 00.00 |
Stained glass, 1 8", 2 layers, full fuse. The fusing tempera- ture will vary depending on the brand of glass, the batch, and even upon the color. Vent the lid. Set the alarm to 500°F. When the alarm sounds, close the lid from venting position and insert peephole plugs.
Set the alarm again, this time to 1350°F. When it sounds, check the glass through the peephole. When the glass fuses to your satisfaction, write down the temperature and hold time for future firings, and press 9, ENTER(Skip Segment).
This will advance you to segment 3, a flash cooling seg- ment. Lift the kiln lid slightly or open the door ajar until the temperature drops to 1050° F. Then close the door/lid. The kiln will cool slowly through the annealing range, then turn off.
Note: A cooling rate of 9999 (FULL) shuts off the warning alarm that sometimes sounds during rapid cooling. For more details about alarms, see page 20.
Glass Slumping Firing Schedule
| Rate | Temp. |
|
Segment | °F/°C | °F/°C | Hold |
1 | 250/138 | 750/398 | 00.00 |
2 | 900/500 | 1250/676 | 00.30 |
3 | 9999/9999 | 1050/565 | 00.00 |
4 | 150/83 | 750/398 | 00.00 |
Stained glass, 1 8", 2 fused layers, 12" circular pieces, slumped into a bowl. Set the alarm to 500° F. When the alarm sounds, close the lid from venting position and insert peep- hole plugs.
Set the alarm again, this time to 1150° F. When it sounds, check the glass through the peephole. When the glass slumps into the bowl, write down the temperature and hold time for future firings, and press 9, ENTER(Skip Segment).
This will advance you to segment 3, a flash cooling seg- ment. Lift the kiln lid slightly or open the door ajar until the temperature drops to 1050° F. Then close the door/lid. The kiln will cool slowly through the annealing range. Then it will turn off and cool to room temperature.
Note: A cooling rate of 9999 (FULL) shuts off the warning alarm that sometimes sounds during rapid cooling. For more details about alarms, see page 20.
Starting a Firing in a Hot Kiln
Sometimes a firing begins in a hot kiln after a power fail- ure, or other interruption. In this case, the Sentry will begin firing from the first segment that matches the current tem- perature. See Power Failures, page 23.
When the Kiln Shuts Off Too Soon
Ceramic Firings
If the kiln fires to completion before the pyrometric wit- ness cone bends, you can turn the kiln back on and keep fir- ing. Simply program a hotter temperature. Then from IdLE , press START. The kiln will begin firing, taking up where it left off.
Note: By looking at the witness cones through a peephole, you will know if the kiln shuts off too soon.
If the kiln shuts off within 100°F/55°C of maturity, and the temperature drops 50°F/28°C or more after the kiln shuts off, do not depend on the witness cones. Once they cool 50°F/28°C after they have been heated to within 100°F/55°C of maturity, they will not bend properly. This is because they form a hard shell.
Wrong Thermocouple Type
If a
15
