Margaret Barlow on sat 5 jan 02
Before I get soundly trounced!! I would like to say that the glaze recipe
that I posted to the list as an example of crazing and shivering, was just
that, an example and this glaze certainly should not be used on anything.
It is one BAD glaze and I would never consider using such a glaze!!
I am writing this in response to a private post that I received telling me
how bad this glaze was. I knew that and I suppose I should have posted that
information along with the glaze, but with all the discussion on lithium
lately, I did not think it was necessary. My error and My apologies!
So here it is! Do not use the glaze recipe I posted!! It is loaded with
lithium and that is BAD!! At 12 and 11% it causes the glaze to pop right
off the clay as it breaks down the intermediate body glaze layer, or buffer
layer.
The only reason I posted this recipe is to show that zinc is not necessary
to cause shivering and crazing, lithium alone can do that!!
In retrospect I suppose it was even irresponsible of me to post the recipe
I reiterate, it is one BAD glaze, please do not even consider using it.
I do not know where the recipe came from but the test was done a few years
ago when I was just beginning to learn about glaze safety. Today I would
not even test a glaze containing lithium carb as there is no need for it as
I see it. If I wanted lithium at all in a glaze, I would use Spodumene and
keep the lithium at or below 2% and even then I would test the safety of the
glaze before using it on anything remotely functional.
I hope this clarifies my position on this glaze, now let the trouncing
begin!!
Margaret
John Hesselberth on sat 5 jan 02
on 1/5/02 6:22 AM, Margaret Barlow at barlowm@PRIMUS.CA wrote:
> Before I get soundly trounced!! I would like to say that the glaze recipe
> that I posted to the list as an example of crazing and shivering, was just
> that, an example and this glaze certainly should not be used on anything.
> It is one BAD glaze and I would never consider using such a glaze!!
Hi Margaret,
Your first letter was a very important contribution. Thanks for going to
the trouble to dig it up and for sending it. While your second note made it
perfectly clear, I think your first one was clear enough that this is not a
good glaze.
Again, thanks. Those kinds of pieces of information are what will allow
someone, someday to complete the puzzle. It is filed in my permanent file
of notes on unstable glazes and I suspect in several other people's also.
Regards,
John
web sites: http://www.masteringglazes.com and http://www.frogpondpottery.com
EMail: john@frogpondpottery.com
"Pots, like other forms of art, are human expressions: pleasure, pain or
indifference before them depends upon their natures, and their natures are
inevitably projections of the minds of their creators." Bernard Leach, A
Potter's Book.
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