 |
|
Kiln Pointers
|
|
|
Cone-Fire or Ramp-Hold? |
The modern digital ceramic kiln has two firing modes: Cone-Fire and Ramp-Hold. (Glass, heat treating, and jewelry kilns have Ramp-Hold only.) Most people use Cone-Fire mode to fire ceramics. It is simple--just enter speed, cone, and hold time. Ramp-Hold mode, by comparison, seems complicated. Ramp-Hold divides the firing into segments, each with a rate, target temperature, and hold time. But some people fire all their ceramics with Ramp-Hold instead of Cone-Fire. Their reasons: 1) The standard thermocouple (temperature sensor) used in ceramic kilns is the K-type. Over its life, the K-type thermocouple drifts in temperature. This means the temperature readout changes slightly with time and wear. To compensate in Cone-Fire mode for temperature drift, you calibrate the thermocouple using a feature called Thermocouple Offset. It raises or lowers the temperature setting of the thermocouple. To compensate in Ramp-Hold mode for temperature drift, on the other hand, just alter the target temperature of the segment that fires the cone to maturity. You don’t have to use Thermocouple Offset. For example, the witness cone on the shelf needs to bend just a little farther. Merely add 5 degrees of temperature rise to the next firing. Instead of programming a target temperature of 2232 deg. F for cone 6, program 2237. If the witness cone is bent slightly too far, you can easily back off 5 or 10 degrees the next time. 2) The latest digital kilns have candling and slow-cool features in Cone-Fire. Candling helps dry the greenware; slow-cool gives certain glazes extra time for full development. In Ramp-Hold, you can program candling, slow cooling, and other features merely by adding more segments. 3) You learn more about firing when you program easy step yourself. 4) You can experiment in Ramp-Hold more than you can in Cone-Fire. Ramp-Hold simplifies the firing of difficult glazes such as crystalline. If a friend or teacher gives you the firing schedule for a glaze, you can modify it easily in Ramp-Hold to obtain the best results for your kiln and materials. I hope you are enjoying the cooler weather. We have had 50F mornings here in Mesquite. With best wishes, Arnold Howard Paragon Industries, L.P. - Better Designed Kilns 2011 South Town East Blvd. Mesquite, TX 75149-1122 Voice: 972-288-7557 & 800-876-4328 / Fax: 972-222-0646 ahoward@paragonweb.com / www.paragonweb.com |
|
|
|
|
|
on:
|
“Custom and standard Kilns and Industrial Furnaces for ceramics, pottery, heat treating, enameling, |
||||