Lili Krakowski on thu 27 oct 11
Heaven knows some days I feel delayed, not so delayed, crazing is going to
happen to me! Ah, well!
There is a theory, maybe there was a theory,it now is considered obsolete,
that with time, "any and all" glazes will craze.
There are many caveats about that. But, essentially, basically, NO glaze
really can adhere to the underlying clay so well nothing can break the
bond.
Slip glazes seem the most craze resistant (the sane, grounded little
darlings!).
But if you think of the suffering a glaze endures, it is a miracle they
don't all craze from the get go.
Expansion and contraction in firing are the best known, most discussed
causes. But of course any pot is subjected to heat variations, and
functional ones more than others.
Functional pots suffer a lot. Into hot water for a wash; filled with cold
water to wash the grapes; into the fridge; onto the table. Back to fridge.
Empty, still cold, into dishwasher. Etc. And any moisture that has gotten
into the clay--even if /when it is a very small amount--the desirable less
than 1.5%--can, over time, break the bond between glaze and clay and allow
crazing.
As to the delay mentioned--a week or so. Don't you believe it. Examine
those pots with a 10x magnifying glass a day or so out of the kiln...you
will see early crazes.
So make sure this badly behaved glaze has enough alumina and silica. Mak=
e
sure it is fired to best temp. Make sure the body absorbs only 1.5%, or
less. Do your own test in your own kiln, do not take the word of the
producer. (Not that producer lies, but that no ones circumstances are
identical.)
Lili Krakowski
Be of good courage
Url Krueger on thu 27 oct 11
Ah, many great ideas have come forth about my
crazing problem. Thanks to all for your comments.
I'm leaning towards too thick glaze layer or underfired
clay body at this time.
Unfortunately I won't be able to try out your
suggestions for a while as we are moving
household, and you know what a disruption
that means.
Since there are several others who have similar
problems I will report back what I find, when I find it.
Thanks again.
Earl
oregon,usa
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