Ron Roy on mon 10 mar 97
>A hearty thanks to all those who responded. I got some great info although
>I neglected to mention that cost is a major consideration. The stones in
>the stores range from $20 - 35, from what I understand, not too different
>in price from some kiln shelves ( correct me if I'm wrong). Also. I would
>like to make this myself and personalize it.
>Based on the info posted and my preferences, here's what I'll probably do:
>1. buy a bag of "death valley" or brown ^10 stoneware clay from Marjon.
>2. Slab roll and cut a 1.5" circle of clay and cut to 20" in diameter. Dry
>it under a cardboard box of rocks so it maintains it shape and doesn't
>3. Bisque and then high fire the stone to ^10 to vitrify, hoping with
>shrinkage it comes to about .75" thick and about 17" in diameter.
>Glazed v. unglazed functional ware part
>4. I will not glaze the stone. I love the color of this clay when is
>high fired. It should not stain or be susceptible to fungus or whatever. I
>made a dinnerware set in a similar fashion which I use everyday and I have
>no problems with staining. They came out really nicely. I used death
>valley clay from Marjon.
>So that's it. Thanks again for all of your suggestions. If any of this is
>really out of line please let me know.
With cone 10 bodies you run into cristobalite problems - especially with
high iron bodies.
If there is significant cristobalite present thermal shock cracking is the
problem at oven temperatures. My dilatometer experiments indicate this
reversible cristobalite inversion happens between 150C (300F) to 250C
(480F). It means - if the ware is not placed in the centre then one side
goes through the expansion before the other side and may crack. There is no
cristobalite in low fire bodies - not through firing anyway. At come 6
there is not enough time for the cristobalite to build up much. Either of
those temperatures would be better.
Evenings, call 416 439 2621
Fax, 416 438 7849
Kris Baum on wed 12 mar 97
Using a ^6 sculpture body, I've made one each of bisque, ^6 unglazed, and
^6 glazed pizza stones for a customer who is willing to try them out for
me. In a few weeks I will post the results.
Kris Baum, Shubunkin Pottery,
Stern HQ on thu 13 mar 97
Question about the pizza stone/baking sheet items: do you have to use ^6
clay or can you use earthenware? When you bake cookies on the glazed
surface, as suggested on this list yesterday, do you have to grease the
surface before putting down the cookie dough? TIA Jeni
On Wed, 12 Mar 1997, Kris Baum wrote:
> ----------------------------Original message----------------------------
> Using a ^6 sculpture body, I've made one each of bisque, ^6 unglazed, and
> ^6 glazed pizza stones for a customer who is willing to try them out for
> me. In a few weeks I will post the results.
> Kris Baum, Shubunkin Pottery,