Pat's Pottery on wed 19 sep 07
Hi John,
I filled in a small hole in the bottom of a stoneware piece with paper =
stoneware clay I bought from Axner. Then I glazed over the patch. It =
worked fine on the inside of the bowl, but a crack formed on the bottom, =
that wasn't there before. What is calcined clay?
Pat
************************************
Pat Parker's Stoneware Pottery
Unique hand made gifts
Web Site: http://www.stonewarepottery.net/
Email address: Pat@stonewarepottery.net
***********************************
John Rodgers on wed 19 sep 07
Calcined clay is clay fines that have been fired to a bisque
temperature. You can patch greenware with paper clay made of the same
greenware clay, or you can patch bisqued clay with paper clay made with
calcined clay, but if you try and patch bisque with greenware clay there
is a big difference in the amount of shrinkage between the two that
takes place when you go to a high fire for glaze and you will wind up
with a crack most times. One thing that I do, depending on where a hole
or crack is located, and the nature of the crack, and that is to mix a
bit of calcined clay with some of the glaze I will be using, and fill
the crack with it. Then I glaze thw whole thing. That usually will seal
the crack, and it will look decent as well. Sometimes not, but most
times will.
Regards,
John Rodgers
Chelsea, AL
Pat's Pottery wrote:
> Hi John,
> I filled in a small hole in the bottom of a stoneware piece with paper stoneware clay I bought from Axner. Then I glazed over the patch. It worked fine on the inside of the bowl, but a crack formed on the bottom, that wasn't there before. What is calcined clay?
> Pat
> ************************************
> Pat Parker's Stoneware Pottery
> Unique hand made gifts
> Web Site: http://www.stonewarepottery.net/
> Email address: Pat@stonewarepottery.net
> ***********************************
>
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