|Monthly Tech-Tip |
In traditional functional ceramics, this term generally refers to glazes that mature at cone 8 and higher. At these temperatures, natural minerals like feldspar, calcium carbonate, etc can be compounded to create glazes that will melt well without the need for powerful (and troublesome fluxes) like zinc oxide, boron or lead. Materials like Alberta Slip and Ravenscrag Slip will melt unassisted to produce beautiful glossy glazes. In addition, high temperatures mean that bodies are higher in quarts and fewer high expansion fluxes are needed so it is much easier to create glazes that do not craze.
Crazed ceramic glazes have a network of cracks. Understanding the causes is the most practical way to solve it. 95% of the time the solution is to adjust the thermal expansion of the glaze.
To potters, stonewares are simply high temperature, non-white bodies fired to sufficient density to make functional ware that is strong and durable.
Ceramic glazes are glasses that have been adjusted to work on and with the clay body they are applied to.
High Temperature (Cone 10) Glaze Recipes
Normally reduction gas fired.
Convert a Cone 10 Glaze to Cone 6 Using Desktop Insight
Learn the chemistry differences between cone 10 and 6 glazes and how to make a glaze melt at a lower temperature without introducing other problems like crazing.
Reducing the Firing Temperature of a Glaze From Cone 10 to 6
Moving a cone 10 high temperature glaze down to cone 5-6 can require major surgery on the recipe or the transplantation of the color and surface mechanisms into a similar cone 6 base glaze.
|By Tony Hansen|
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