Cone 8 temperature
Orton cone 8 bends at 2280 °F (1249 °C) at 108 °F/hr and 2320 °F (1271 °C) at 270 °F/hr. It sits in the high fire range — cone 32 of 38 on the chart, counting up from 022.
108 °F/hr · 60 °C/hr
2280 °F1249 °C
Medium — the rate most charts quote
270 °F/hr · 150 °C/hr
2320 °F1271 °C
Fast — typical of a quick electric firing
Orton self-supporting regular cones; rate measured over the last 200 °F of the firing. Source: Orton °F chart; °C converted. Cones measure heat-work, so a controller set to 2280 °F is not the same as firing to cone 8 — put a witness cone on the shelf.
Cone 8 is not cone 08
Cone 08 — with the leading zero — is 552 °F cooler (1728 °F), in the low fire range. Read the zero as “oh”; a glaze labeled for one will not behave at the other.
What cone 8 is used for
High fire — Traditional stoneware and porcelain, especially in gas reduction. Cone 10 is the classic high-fire target; cone 9–10 is where shinos, celadons, and copper reds live.
Cone 8 compared
| Comparison | At 108 °F/hr | Difference (medium) | Difference (fast) | |
|---|---|---|---|---|
| cone 8 vs cone 08 | 1728 → 2280 °F | 552 °F (307 °C) | 567 °F (315 °C) | cone 8 is hotter |
| cone 8 vs cone 7 | 2262 → 2280 °F | 18 °F (10 °C) | 25 °F (14 °C) | cone 8 is hotter |
| cone 8 vs cone 9 | 2280 → 2300 °F | 20 °F (11 °C) | 16 °F (9 °C) | cone 9 is hotter |
| cone 8 vs cone 06 | 1828 → 2280 °F | 452 °F (251 °C) | 465 °F (258 °C) | cone 8 is hotter |
| cone 8 vs cone 04 | 1945 → 2280 °F | 335 °F (186 °C) | 349 °F (194 °C) | cone 8 is hotter |
| cone 8 vs cone 5 | 2167 → 2280 °F | 113 °F (63 °C) | 115 °F (64 °C) | cone 8 is hotter |
| cone 8 vs cone 6 | 2232 → 2280 °F | 48 °F (27 °C) | 51 °F (28 °C) | cone 8 is hotter |
| cone 8 vs cone 10 | 2280 → 2345 °F | 65 °F (36 °C) | 61 °F (34 °C) | cone 10 is hotter |
Convert
cone 8 bends at
2280 °F(1249 °C)
At 108 °F/hr (60 °C/hr) — medium. Faster firing → the same cone bends hotter. Everything about cone 8 →
Questions
- What temperature is cone 8?
- Orton cone 8 bends at about 2280 °F (1249 °C) when the kiln climbs at 108 °F per hour, and about 2320 °F (1271 °C) at 270 °F per hour. Cones measure heat-work — temperature over time — so the faster you fire, the hotter the kiln has to get for the same cone to bend.
- What is cone 8 in Celsius?
- 1249 °C at 108 °F/hr (60 °C/hr) and 1271 °C at 270 °F/hr (150 °C/hr), converted from Orton's Fahrenheit chart for self-supporting regular cones.
- Is cone 8 the same as cone 08?
- No — and this is the most common cone mix-up. Cones with a leading zero count down toward cone 1, so cone 08 is cooler than cone 8: about 1728 °F versus 2280 °F at 108 °F/hr, a difference of 552 °F. Read the zero as "oh", not as nothing.
- What is cone 8 used for?
- cone 8 sits in the high fire range. Traditional stoneware and porcelain, especially in gas reduction. Cone 10 is the classic high-fire target; cone 9–10 is where shinos, celadons, and copper reds live.
- How far is cone 8 from cone 7 and cone 9?
- At 108 °F/hr, cone 7 bends 18 °F cooler (2262 °F) and cone 9 bends 20 °F hotter (2300 °F). One cone step is not a fixed number of degrees — the spacing varies across the chart.
Firing to cone 8? Claybench schedules the kiln around it.
Clay body, glazes, and firing schedule are matched by cone before a plan is saved.