Self Supporting Cones 04 Pack of 20

Description

04 Self Supporting Witness Cones - Pack of 25    

Self-Supporting Cones are the most accurate and easiest to use pyrometric cones available. 
They feature a built-in base for support during firing and require no cone holder or plaque. Correct height (1 ¾”) and angle (8°) are built in to help insure reproducible firings time after time. 
Self-Supporting Cones are popular as witness cones on the kiln shelf to visually record and evaluate the heat work (the effect of temperature and time at temperature) in different locations throughout  the kiln.
Pyrometric cones are recommended by glaze and kiln manufacturers to assure the proper amount of heat work was achieved during firing.  Achieving the proper amount of heatwork allows the optimum ceramic properties and colors to be developed during the firing process.  Pyrometric Cones will also help identify any subtle changes taking place inside the kiln before they impact your ware (changes over time due to thermocouple drift, degrading heating elements, etc.).
Thermocouples only measure temperature at one point inside the kiln.  Pyrometric cones can be placed throughout the ware setting so you can easily monitor the heatwork your kiln produces where your product is being fired. 

3 cone method for monitoring heat-work
Pyrometric cones are slender pyramids made from about 100 carefully controlled compositions. Each cone number is unique in measuring temperature within a small temperature range (less than 30°C). Cones measure the amount of heat absorbed. As the cone nears its maturing range, it softens and the tip begins to bend, drawn down by the influence of gravity.

Pyrometric cones are useful in determining when a firing is complete, if the kiln provided enough heat, if there was a temperature difference in the kiln or if a problem occurred during firing. 
Cones are made from carefully controlled compositions and they bend in a repeatable manner (over a relatively small temperature range- less than 40ºF). 
Small (junior) cones are used in a Kiln-Sitter™.

Cone/Temperature Conversion Chart
Cone	Temp at 108ºF/hr	Temp at 270ºF/hr	Kiln Color	Ware and Glaze Types
10	2345	2381	White	Stoneware Glaze
9	2300	2336
8	2280	2320
7	2262	2295
6	2232	2269		Porcelain Bisque
5	2167	2205
4	2124	2161		Porcelain Glaze
3	2106	2138
2	2088	2127
1	2079	2109
01	2046	2080	Yellow
02	2016	2052
03	1987	2019
04	1945	1971
05	1888	1911
06	1828	1855		Bisque,Low Glaze
07	1789	1809	Orange	Red Family Glazes
08	1728	1753
09	1688	1706
010	1657	1679
011	1607	1641
012	1582	1620
013	1539	1582	Red
014	1485	1540
015	1456	1504
016	1422	1465
017	1360	1405		Glass Sagging
018	1319	1353		China Paints
019	1252	1283		Metallics, Lusters
020	1159	1180	Dull Red	Decals
021	1112	1143		Glass Paint
022	1087	1094