Ron Roy on fri 28 nov 03
Hi Terry,
What cone were they bisqued to and how fast cooled - silica sand is quartz
- which inverts at 573C - perhaps getting the tiles off the shelves a bit
will promot more even cooling and stop the dunting - if it is that.
RR
>One of our folks here at Nottingham is moving from graphics to art deco
>carved tiles. She is using a sanded white cone 10 stoneware clay from
>Ardvark ( Hopkins White standard ). These tiles are 1/2 - 3/4 inch
>thick often with fairly deep relief carving.
>Problem with her last batch of tiles was craking which remained fairly
>thin and had the glaze healed over the cracks. Tiles were glazed bisque
>right after a long rainy week and fired on a slow Skutt cone 6 program.
>The clay is rolled several times at opposite angles using a Baily slab
>roller and the tiles are dried very slowly. This is the first time the
>problem has occured.
>My thought is that the tiles contained lots of moisture from the week
>of high ambient weather and fairly heavy glazing ( three brushed on
>coats) and cracked due to too fast a firing.
>
>Any ideas / help on this ??
Ron Roy
RR#4
15084 Little Lake Road
Brighton, Ontario
Canada
K0K 1H0
Phone: 613-475-9544
Fax: 613-475-3513
terry sullivan on fri 28 nov 03
One of our folks here at Nottingham is moving from graphics to art deco
carved tiles. She is using a sanded white cone 10 stoneware clay from
Ardvark ( Hopkins White standard ). These tiles are 1/2 - 3/4 inch
thick often with fairly deep relief carving.
Problem with her last batch of tiles was craking which remained fairly
thin and had the glaze healed over the cracks. Tiles were glazed bisque
right after a long rainy week and fired on a slow Skutt cone 6 program.
The clay is rolled several times at opposite angles using a Baily slab
roller and the tiles are dried very slowly. This is the first time the
problem has occured.
My thought is that the tiles contained lots of moisture from the week
of high ambient weather and fairly heavy glazing ( three brushed on
coats) and cracked due to too fast a firing.
Any ideas / help on this ??
Thanks,
Terry Sullivan
Nottihgham Arts
San Marcos, CA
Nanci Bishof on sat 29 nov 03
Terry,
Often if there is too great a difference in the thickness of the clay from
carving the result will be cracking. Does it happen with the same tile design
consistently in the same area?
___ ______
My attempt at illustrating ____/ \ /
this on computer. \___/ < prone to cracking
nanci
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