Mark Cortright on wed 1 feb 12
Date: Mon, 30 Jan 2012 21:40:38 -0500
From: Eva Gallagher
Subject: problems with cone 10 Bmix dunting?/cracking
Hi,
Has anyone else had any problems with Bmix cone 10 recently? In our
Guild a
member's flat plates cracked after they were out of the kiln and a few
weeks
ago a tall vase of mine cracked. The plates were not glazed on the
bottom so
glaze fit/thickness could have been the problem, but my piece was glazed
with Wirtz shino inside and M Davis outside. The MD is well crazed and I
assume the Wirtz as well though hard to tell. About an hour after being
taken out I heard a loud crack an several smaller ones and two long
cracks
appeared on either side of my handbuilt slab vase. Never had that happen
before with either handbuilt or thrown Bmix - it's always been a very
trouble free clay for us.
Eva Gallagher
Deep River Ontario
http://newfoundoutpotter.blogspot.com/
I have used b-mix for over 25 years .I mainly use many tons of daves
porcelian per year but do some b mix as well and it is not the best
clay for hand building. I have seen it dunt a lot in slab construction-
the more matt glazes put the most stress on it
I suggest using another body like laguna's half and half for slab work
(get the 1/2 with larger grog WC 382) its a white body and will work
great with slabs and hand work
I have had b mix bloat-dunt-crack all in the glaze fire-laguna has had
issues with it but they were many years ago-(over 15)
Yes it throws well but its very easy to overfire or over reduce and
glaze fit is key to keeping it working well-slow cooling helps also
hope this helps
Mark Cortright
www.liscomhillpottery
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