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homebuilt kiln/greenware glazes

updated thu 23 may 02

 

Snail Scott on wed 22 may 02


At 08:30 AM 5/22/02 -0700, you wrote:
>Is the reason for high clay content in single fire glazes to keep the
>glaze from jumping off the pot and making me clean kiln shelves?


Yeah, pretty much.

It's to create an unfired glaze layer that will
shrink in tandem with the raw clay. I often think
it's more important in reverse, though...that
glazes for bisqueware need to have low clay
content (low green shrinkage). Glazes for
greenware tend to do best with high clay content,
but IMHO it's not essential. It's more of a
convenience, allowing the use of all those nice
slip-glazes. (Some glazes designed for bisque
will crack off green clay due to insufficient
shrinkage, but I believe it's less common than
for greenware-style glazes to crack off due to
excess shrinkage on bisque.)

By the way, I generally try to glaze sometime
after leather-hard, but while there's still
plenty of moisture in the clay. It seems to
reduce the damage (due to moisture absorption)
that can occur when glazing bone-dry work.

-Snail