centa on thu 2 mar 00
Hi,
I'm experimenting with slab formed platters over bisque or plaster hump
molds and am having problems with cracking even with feet. This last one
I waited until leather hard then put an engobe on it and it began to
crack at the edge inward. I don't know if it would have anyway or not.
In this case should I have waited until bone dry? Would a more plastic
clay body be adviseable. This one was more of a scultpure body with
noticeable grog. I'm firing mid range red and white clays.
Thanks,
Centa
Paul Taylor on tue 7 mar 00
Dear Centa
I have thought longer about your problem.
I used to rawglaze a lot. To get glaze on a pot destined to crack ,eg a
teapot. I used to glaze the pot in two stages outside first and then when
the pot had dried - the inside. This was successful because dipping in two
stages meant the pot did not get over wet and
the handles etc had not dried out compleatly so they did not disintegrate.
I expect there are some places where this is illegal but it worked for me
and should work with your slip if it is not too thick. Defloculating the
slip and taking some water out of it may help but that will lessen the
shrinkage and may make it run in strange globs - There is a fancy name for
that but I forget it .
Paul T
----------
>From: centa
>To: CLAYART@LSV.UKY.EDU
>Subject: what clay makes for large hump molded platters?
>Date: Thu, Mar 2, 2000, 6:41 pm
>
>----------------------------Original message----------------------------
>Hi,
>I'm experimenting with slab formed platters over bisque or plaster hump
>molds and am having problems with cracking even with feet. This last one
>I waited until leather hard then put an engobe on it and it began to
>crack at the edge inward. I don't know if it would have anyway or not.
>In this case should I have waited until bone dry? Would a more plastic
>clay body be adviseable. This one was more of a scultpure body with
>noticeable grog. I'm firing mid range red and white clays.
>
>Thanks,
>Centa
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