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crystalline glaze in gas kiln

updated wed 31 jul 96


Alan Wainright on tue 23 jul 96

Caroline Jacobs ( wrote:

"I want to use porcelain with crystalline glaze, but I can't get
hold of a high-fire electric kiln. How can I get the same finish
using a high-fire gas kiln?"

I checked with Richey Bellinger (a name you may hear a lot in my
postings: he's our R&D specialist) for how to do this, & here's
his answer:

"You could try using crystalline glazes in a gas kiln, but it
might be a little tricky. The key is controlling the temperature
of the firing. Generally, you heat the ware to the point where
the glaze melts, then back off the temperature 30-50 degrees &
soak it there for 3 hours or so, allowing the crystals time to

"In an electric kiln, especially one of the new
computer-controlled ones, it's pretty easy. In a gas kiln,
however, it's more difficult. You'd really need a pyrometer to
control the heat well.

"The second catch is that crystalline glazes have unique &
special formulas. The long heat soak may be risky to other pieces
in the kiln which don't have the crystalline glaze."

I hope this helps. Good luck!