Kiln Firing

The main kiln is an electric Skutt KTM 1027-3 kiln fired to a target of Cone 6. The kiln is vented with a Skutt Envirovent 2.

The test kiln is an electric Paragon Caldera XL kiln, also fired to a target of Cone 6. It's not vented.

Being electric kilns the atmosphere is oxidation.

Two firing schedules are discussed, a natural cooling schedule and a controlled cooling (down fire) schedule.

1) Natural Cooling Schedule

Both kilns are programmed with the following, slow ramp, natural cooling firing schedule, modeled from Kline.

Using self-standing cones and trial and error, "my" Cone 6 is reached using a target temperature of ~2210 Fahrenheit rather than 2232, the canonical Cone 6 temperature. Higher target temperatures push well into Cone 7.

Here are examples of self-standing cones from each kiln from their latest firing:

The main kiln recorded 30% Cone 7 (top), 30% Cone 7 (middle) and 80% Cone 6 (bottom) with a peak of 2210 degrees Fahrenheit. So the upper portions of the kiln are pushing into Cone 7 while the bottom more or less hits Cone 6.

The test kiln recorded 25% Cone 7 (top) and Cone 6 exactly (bottom) at a peak of 2215 degrees Fahrenheit.

These results show both kilns are creating very similar atmospheres.

Addendum: As of 1/9/26, having logged over 60 glaze firings (and about the same number of bisque firings), it's been observed the upper portion of the main kiln fires over Cone 6 at about 30 - 40% Cone 7. The temperature of the bottom of the kiln is more variable reaching between 30% - 80% Cone 6. The variability is due to how the kiln is loaded. This has been a successful firing schedule.

2) Controlled Cooling (Down Fire) Schedule

In late 2025 a new firing schedule with controlled cooling was adopted with good initial results.

The schedule, also derived from Kline, is provided below. Modifications include a 15 minute soak at the top and controlled cooling to 1500 F instead of 17oo F.

The corresponding cone photo is shown below.

The main kiln recorded 20% Cone 7 (top), 25% Cone 7 (middle) and 60% Cone 6 (bottom) with a peak of 2210 degrees Fahrenheit, similar to the non-cooling schedule.