Ramp, target, hold
Firing schedule builder
Each segment takes its temperature change divided by its rate, plus its hold. Skutt's medium-speed profile for cone 6, five segments from 21 °C (70 °F), takes about 8 hours 28 minutes to reach 1222 °C (2232 °F).
Schedule
Cone 6 glaze, medium · start 21 °C (70 °F)
8 h 28 minto the end of the last segment
Peak 1222 °C (2232 °F) · cooling after the last segment is not counted
| # | Ramp | Target | Hold | Time | Ends at |
|---|---|---|---|---|---|
| 1 | Heat at 111.1 °C/h (200 °F/h) | 121 °C (250 °F) | — | 54 min | 54 min |
| 2 | Heat at 222.2 °C/h (400 °F/h) | 538 °C (1000 °F) | — | 1 h 53 min | 2 h 47 min |
| 3 | Heat at 100 °C/h (180 °F/h) | 621 °C (1150 °F) | — | 50 min | 3 h 36 min |
| 4 | Heat at 166.7 °C/h (300 °F/h) | 1083 °C (1981 °F) | — | 2 h 46 min | 6 h 23 min |
| 5 | Heat at 66.7 °C/h (120 °F/h) | 1222 °C (2232 °F) | — | 2 h 5 min | 8 h 28 min |
Top 100 °C of this firing: 1 h 30 min, an effective 67 °C/h (Orton's rule of thumb). The closest chart column is 60 °C/h, where the nearest self-supporting cone to 1222 °C is cone 6 (1222 °C). A rough guide: put witness cones in the kiln to see what it really did.
How to use the schedule builder
Pick a starting point, then edit any rate, target or hold, or add segments up to twelve. A target below the previous one is a controlled cooling segment. The total stops at the end of the last segment; natural cooling afterwards takes longer.
- The presets are starting points; follow your kiln's and your clay's guidance. The cone 04 profiles are as printed in Skutt's KilnMaster manual. For cone 06 and 6 the manual says the rates stay the same and segment 4 ends 250 °F below the cone's temperature, so those presets apply that rule.
- Effective heating rate: Orton's rule of thumb divides 100 °C by the hours spent in the top 100 °C, holds included. It tells you which column of the cone chart to read.
- Holds: as a guide from Orton, firing 10 °C lower needs about 20 minutes of hold for the same heat-work, 20 °C lower 40 to 60 minutes, and 30 °C lower about 2 hours.
Sources
- Presets: Skutt KilnMaster Operating Manual, Edition 4 (May 2002), Cone Fire mode: the slow, medium and fast profiles for cone 04 in °F, the rule for other cones, and the 108 °F/h self-supporting cone table (cone 06 1828 °F, cone 6 2232 °F). Times assume a start at 70 °F (21 °C).
- Effective heating rate: Orton, Pyrometric Cones Resources. Holds: Orton, Cones and Firing (2013). Cone temperatures: Orton cone chart, cones 022-12 (March 2026).
Questions
How long does a cone 6 glaze firing take?
Skutt's medium-speed profile for cone 6 takes about 8 hours 28 minutes from 21 °C, and the slow one about 14 hours 10 minutes, before cooling. Your kiln, load and schedule will differ.
How long does a bisque firing take?
Skutt's slow cone 04 profile, meant for hand-thrown pottery, adds up to about 12 hours 33 minutes; its medium profile about 7 hours 31 minutes.
How do I work out a segment's time?
Divide the temperature change by the rate and add the hold. Heating from 621 °C to 1083 °C at 166.7 °C an hour takes 462 ÷ 166.7, about 2 hours 46 minutes.