gambaru on mon 24 nov 97
Could there be a possible change in a glaze ingredient/s that has changed
the expansion value of your glaze ? As you are only glazing one side ,
this could be setting up alot of stress possibilities. Also, is this group
of work from a new batch of clay and a change of properties in the clay
body ingredients, therefore giving you the expansion change in the clay
body. If memory serves me, I think there were some posts about a problem
in a clay body that was traced to a change in OM#4. No help, but maybe an
answer pathway. MB
Carolynn Palmer on tue 25 nov 97
I think it was indeed the new shipment of Kentucky Stone, a clay purchased
from K-T who also mine Old Mine #4 that caused the cracking (coincidence, I
think not).
On the advice of the K-T people we had been adding 30% Flint. We mixed the
next batch of clay without any flint and no problem so far.
Does anyone know why the ceramic engineers always recommend so much flint be
added to a clay body? Most have advised 50%! This never works for me. And
I have always wondered what mesh flint are they talking about - sometimes I
can only get 20 mesh or 395 or 295 - nothing in between, from my supplier.
I still mourn the passing of Pine Lake and other great clays I loved.
Carolynn Palmer, Somerset Center, Michigan
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