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80-250C (176-482F) | 80-250C (176-482F) | 120C (248F) | 150C (302F) | 180C (356F) | 185C (365F) | 200-450C (392-842F) | 200-1000C (392-1832F) | 200C (392F) | 210-280C (410-536F) | 260C (500F) | 290C (554F) | 300C (572F) | 300-330C (572-626F) | 300C (572F) | 370-700C (698-1292F) | 370C (698F) | 400C (752F) | 425-650C (797-1202F) | 450-650C (842-1202F) | 470-1200C (878-2192F) | 500-600C (932-1112F) | 512C (953F) | 540-600C (1004-1112F) | 650-900C (1202-1652F) | 750-850C (1382-1562F) | 750-1000C (1382-1832F) | 760C (1400F) | 760C (1400F) | 787C (1448F) | 800-1100C (1472-2012F) | 815C (1499F) | | 843C (1549F) | 850C (1562F) | 850-950C (1562-1742F) | 850C (1562F) | 870-900C (1598-1652F) | 871C (1599F) | 900C (1652F) | 900-1000C (1652-1832F) | 900C (1652F) | 926C (1698F) | 932C (1709F) | 950-1050C (1742-1922F) | 954C (1749F) | 980C (1796F) | 982C (1799F) | 990C (1814F) | 1025C (1877F) | 1025-1325C (1877-2417F) | 1050-1200C (1922-2192F) | 1050C (1922F) | 1065-1120C (1949-2048F) | 1082C (1979F) | 1100-1450C (2012-2642F) | 1100C (2012F) | 1100C (2012F) | 1100C (2012F) | 1100C (2012F) | 1300C (2372F) | 1325C (2417F) | 1330C (2426F) | 1360C (2480F) | 1418-1428C (2584-2602F) | 1420C (2588F) | 1550C (2822F) | 1565C (2849F) | 1650C (3002F) | 1785C (3245F) | 1990C (3614F) | 2300C (4172F) | 2320C (4208F)

815C (1499F)

Calcium carbonate, talc finished gassing

Related Information

LOI horse race with a surprising winner and loser


A chart showing weight-loss vs firing temperature for common ceramic materials

This picture has its own page with more detail, click here to see it.

This chart compares the decompositional off-gassing (% weight Loss on Ignition) behavior of six glaze materials (there are many more). Each was heated through the range 500-1700F at 350F/hr. It is amazing how much weight some can lose on firing. For example, 100 grams of calcium carbonate generates 44 grams of CO2! Magnesium carbonate even more. But the main message of this chart is that some late gassers overlap early melters. That can be a problem (causing glaze bubbles, blisters, pinholes). The talc in this test is an example: It did not finish gassing until 1650F. Yet many fritted and Gerstley Borate glazes have already begun melting by then.

There are two takeaways here. The biggest weight loser is not the biggest troublemaker. What matters is how gas release overlaps glaze sealing. Calcium carbonate illustrates this; its high carbonate content can still produce a clear glaze (when gases can clear ahead of any melting). And the talc, although having a small LOI, is a potential troublemaker when the glaze melt cannot effectively clear the bubbles.

Links

Temperatures Decarbonation (200-1000)
Glossary Carbon Burnout
Ceramic materials, especially clays, often contain carbon and organic compounds. When they are fired in a kiln, these must burn out, often producing complications.

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