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more cracking tiles

updated tue 30 mar 99

 

Lori Bradley on sun 28 mar 99

Hi everyone,

I read the posts about cracking tiles with interest because I'm having
similar problems. I'm working with rather large (up to 10" x 10") tiles
with irregular borders. Most of them have a very high relief surface, some
are carved directly, others created with press molds. I'm using low-fire
(04) white earthenware. I've been getting hairline cracks that don't run
through the entire tile, but maybe an inch or two into it. The ones with
the most relief crack the most. I've tryed scoring the backs of the tiles,
carving into the highest areas from the back when leather hard, drying
slowly for a long, long time, and varying the clay recipe by adding more
sand and fine grog. These efforts are helping but I'm still getting a
fairly high rate of cracking. Does anyone out there have any suggestions.
Are there things I can do during firing to lessen this problem? I'm using
an electric kiln. TIA!

Also, I attended NCECA this year for the first time and what great fun.
Saw several inspiring panel presentations and met many inspiring people!
What a great group. It made me even more glad to be involved with this
exciting medium.

Lori Bradley
sassafra@tiac.net

Wendy Neilson on mon 29 mar 99

I too fire tiles and mostly at least 12 x 12"... .. try a long bisgue. I do
5 hours at 100 degrees per hour followed by 200 degrees an hour to cone 05.
Obviously slow drying between sheets of plaster board. So far so good!..
fingers crossed of course. Wendy