Orton | LRB4
Large Regular Pyrometric Cone 4
Cone 4 in Orton's large regular series, the witness cone that stands on the kiln shelf beside the ware. Its bend after the firing shows whether the kiln reached, missed or passed cone 4, which a controller reading on its own cannot tell you.
$35
Suggested retail price. In-store prices and availability may vary by location.
This is Cone 4 in Orton's large regular LRB series, the standard witness cone for the kiln shelf. Orton lists it bending at 1160°C (2120°F) when the last 100°C of the firing climbs at 60°C an hour, and at 1181°C (2158°F) at 150°C an hour. A cone responds to time and temperature together, not temperature alone, so the number it bends at depends on how fast the kiln is climbing. Orton lists cones in this part of the range for porcelain, stoneware, china, floor tile and structural clay. The cone does not stand on its own. Set it in a cone plaque, clay pat or wire holder with 51 mm (2 in) showing above the mount and leaning at 8 degrees. If that height is out by 6 mm (¼ in) the bend shifts by more than half a cone.
- Cone 4
- Bends 1160°C (2120°F) at 60°C an hour
- Bends 1181°C (2158°F) at 150°C an hour
- 63.5 mm (2½ in) tall
- Mounts in a cone plaque, clay pat or wire holder
- 51 mm (2 in) exposed, leaning at 8 degrees
- Finished at a 90 degree bend
Downloads
Orton’s cone charts and guide to cones and firing.
