Share from Insight-live.com (Lab Documentation and Calculation System) by Digitalfire. https://digitalfire.com
Firing Schedule Name
Cone 03 hold-rise-drop-hold
Degrees (Fahrenheit or Celcius)
F
Schedule Type
Rate
Start Time and Temperature
8:01 am at 80F
Program
| Step | Degrees/Hr | Temperature Monitor |
Hold Time |
Accumulated hrs:min |
Time | Note |
|---|---|---|---|---|---|---|
| 1 | 400 | 240 | 60 | 1:24 | 9:25 am | |
| 2 | 350 | 1850 | 30 | 6:00 | 2:01 pm | |
| 3 | 108 | 1950 | 10 | 6:55 | 2:56 pm | |
| 4 | 500 | 1850 | 30 | 7:07 | 3:08 pm |
Notes
Used to glaze fire Zero3 porcelain and stoneware. However, there is a caution about bisquing these frit-containing bodies: They will vitrify in a typical firing, you must reduce the temperature to around 1500F (if ware is not absorbent enough fire lower). Note: this schedule is for the glaze firing, the previous two sentences simply referenced what is needed for the bisque.
This can start and finish more than once in a working day. Step 2 can often be done as fast as your kiln will go (cold-to-cold in three hours is possible).
The soak at 240F does not fracture ware even though it is above the boiling point of water. We find this is needed to be sure ware is sufficiently dry to withstand the rapid ascent to 1850. If your ware is thicker a slower ascent may be needed.
The 1850 soak on the way up clears the clouds of microbubbles. The 1850 soak on the way down heals the defects (blisters, pinholes) because the increasing viscosity is enough to overcome the surface tension holding bubbles from breaking).
It may be necessary to alter the last step if any imperfections are present. Try dropping to 1800 or 1750 and holding there. An additional step could be added to cool at 100F/hr down to 1500.