"PLC6CR" Firing Schedule

Cone 6 Crystal Glaze Plainsman

With the advent of computer controlled kilns, producing crystal glazes at medium and high temperatures is quite easy, just use a really fluid zinc glaze and fire a schedule that gives them opportunity to grow.

Adjust the final temperature on step 3 to match the temperature your kiln reads when it reaches cone 6.

Note that almost everyone who uses crystalline glazes either does not notice or has accepted the crazing that these naturally produce on typical porcelain clay bodies at middle at high temperatures. This is not necessary, a high expansion clay body can be employed to prevent this.

Step	°C	°F	Time
1	176°C/hr to 372C	316°F/hr to 701F	2:08
2	398°C/hr to 1093C	716°F/hr to 1999F	3:57
3	65°C/hr to 1210C	117°F/hr to 2210F	5:45
4	398°C/hr to 1093C	716°F/hr to 1999F	6:03
5	398°C/hr to 1037C	716°F/hr to 1898F	6:11

Start temperature assumed: 25°C or 75°F
"Fahrenheit degrees" is not the same as "degrees Fahrenheit". A 100° reading on a Fahrenheit thermometer is equal to a 37° reading on a Celcius thermometer. But "100 Fahrenheit degrees of temperature change" is equivalent "55 Celsius degrees of change". That is an important distinction to understand the above temperature conversions.

Related Information

Links

Recipes	G2902B - Cone 6 Crystal Glaze
Glossary	Crystalline glazes A type of ceramic glaze made by potters. Giant multicolored crystals grown on a super gloss low alumina glaze by controlling multiple holds and soaks during cooling

By Tony Hansen
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