If you've been working with Art Clay, PMC, or glass, you'll probably understand how the Orton ramp-hold programmer works. However, if you want to work with ceramics, you'll need to understand pyrometric cones.

Pyrometric cones are slender pyramids, made from about 100 carefully controlled compositions, that measure the effect of time and temperature. As the cone nears its maturing range, it softens and the tip begins to bend down under it's own weight. Ceramics are usually sold with instructions, which include the cone number.

Cone-Fire, generally used for ceramics, pottery, stoneware, glazes, china painting, and decals, fires to a set pyrometric cone number listed in the Orton cone tables. It's not designed for Art Clay, heat treating, glass work, and enameling.
Cone-Fire will only be successful if you understand how cones and cone numbers work. Unlike a programmer, a cone is a visual indicator that your work has been fired for the correct combination of kiln temperature, kiln atmosphere, and time.

If you bought a ceramics kiln with a cone-fire programmer, you can fire using cones because the programmer is set up to use cone numbers. If you have a ramp-hold programmer, you'll need to be able to convert cone numbers to temperature and time. Of course, you can't use a cone that matures at a higher temperature than your kiln can maintain.

Cone numbers were originally set from 1 to 10, 1 being the coolest. However, cooler cones were introduced from 022 to 01. To fire faster or slower than the segments listed, change the rates by 10 - 20%. However, the last segment should always be 108. The list below starts with the coolest.

CENTIGRADE AND FAHRENHEIT

The metric system, used in the EU and most other countries, uses centigrade. The US and a few other countries use fahrenheit. There are simple ways of converting:

centigrade = (fahrenheit - 32) divided by 9 then multiplied by 5

fahrenheit = (centigrade divided by 5 then multiplied by 9) + 32

Using the centigrade scale, water freezes at 0°C and boils at 100°C. Using the fahrenheit scale, water freezes at 32°F and boils at 212°F.

PROGRAMMING PYROMETRIC CONES

Cone 022
Segment 1   Rate: 396   Temperature: 0979
Segment 2   Rate: 108   Temperature: 1087

Cone 021
Segment 1   Rate: 396   Temperature: 1004
Segment 2   Rate: 108   Temperature: 1112

Cone 020
Segment 1   Rate: 396   Temperature: 1051
Segment 2   Rate: 108   Temperature: 1159

Cone 019
Segment 1   Rate: 396   Temperature: 1144
Segment 2   Rate: 108   Temperature: 1252

Cone 018
Segment 1   Rate: 396   Temperature: 1211
Segment 2   Rate: 108   Temperature: 1319

Cone 017
Segment 1   Rate: 396   Temperature: 1252
Segment 2   Rate: 108   Temperature: 1360

Cone 016
Segment 1   Rate: 396   Temperature: 1314
Segment 2   Rate: 108   Temperature: 1422

Cone 015
Segment 1   Rate: 396   Temperature: 1348
Segment 2   Rate: 108   Temperature: 1456

Cone 014
Segment 1   Rate: 396   Temperature: 1377
Segment 2   Rate: 108   Temperature: 1485

Cone 013
Segment 1   Rate: 396   Temperature: 1431
Segment 2   Rate: 108   Temperature: 1539

Cone 012
Segment 1   Rate: 396   Temperature: 1474
Segment 2   Rate: 108   Temperature: 1582

Cone 011
Segment 1   Rate: 396   Temperature: 1499
Segment 2   Rate: 108   Temperature: 1607

Cone 010
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 180   Temperature: 1549
Segment 4   Rate: 108   Temperature: 1657

Cone 09
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 180   Temperature: 1580
Segment 4   Rate: 108   Temperature: 1688

Cone 08
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 180   Temperature: 1620
Segment 4   Rate: 108   Temperature: 1728

Cone 07
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 180   Temperature: 1681
Segment 4   Rate: 108   Temperature: 1789

Cone 06
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 180   Temperature: 1720
Segment 4   Rate: 108   Temperature: 1828

Cone 05
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 180   Temperature: 1780
Segment 4   Rate: 108   Temperature: 1888

Cone 04
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 180   Temperature: 1837
Segment 4   Rate: 108   Temperature: 1945

Cone 03
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 180   Temperature: 1879
Segment 4   Rate: 108   Temperature: 1987

Cone 02
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 180   Temperature: 1908
Segment 4   Rate: 108   Temperature: 2016

Cone 01
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 180   Temperature: 1938
Segment 4   Rate: 108   Temperature: 2046

Cone 1        
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 162   Temperature: 1863
Segment 4   Rate: 108   Temperature: 2079

Cone 2
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 162   Temperature: 1872
Segment 4   Rate: 108   Temperature: 2088

Cone 3
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 162   Temperature: 1890
Segment 4   Rate: 108   Temperature: 2106

Cone 4
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 162   Temperature: 1908
Segment 4   Rate: 108   Temperature: 2124

Cone 5
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 162   Temperature: 1951
Segment 4   Rate: 108   Temperature: 2167

Cone 6
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 162   Temperature: 2016
Segment 4   Rate: 108   Temperature: 2232

Cone 7
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 162   Temperature: 2046
Segment 4   Rate: 108   Temperature: 2262

Cone 8
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 162   Temperature: 2064
Segment 4   Rate: 108   Temperature: 2280

Cone 9
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 162   Temperature: 2084
Segment 4   Rate: 108   Temperature: 2300

Cone 10
Segment 1   Rate: 324   Temperature: 1022
Segment 2   Rate: 153   Temperature: 1112
Segment 3   Rate: 162   Temperature: 2129
Segment 4   Rate: 108   Temperature: 2345