[Clayart] Snow Flake Crackle #4

David Woof woofpots at hotmail.com
Fri Aug 31 13:27:53 EDT 2018


Penny if you are sure you are burning out the clay crud (mel's word) to prevent off gassing thru the glaze, I would next suspect the Neph sy and test for holds near end of glaze maturation to allow adequate time for off gassing and subsequent sealing and healing over of the pin holes/craters....

As soon as glazes turn visually glossy as seen thru peeps I initiate a hold. At times this hold time is where I reach my desired cone falling position.  Although my L&L is fully computer controlled I still stay in the drivers seat and shut down manually by visually observing cone maturation.


As you may know; a hold at maturation temp many times results in over firing which aside from runny glazes which can wreak havoc with a good crackle but can also de-vitrify the glaze causing burned out areas and more holes/craters.   Probably a clumsy sentence or explanation as well bt I'm sure you get the point and now I must go out and install side railings on the ramp the old dog uses because he can no longer climb the front stoop steps and if he topples over the edge of the ramp it will b difficult to extract him from the narrow confines he will fall into. Poor old coot is still hanging on to life, willow bark keeps him pain free, he still gives and receives love and I don't have the heart to whack him. Enough killing of innocents out there, don't u think???


David Woof

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From: Clayart <clayart-bounces at lists.clayartworld.com> on behalf of Penny Berglund <farmgrl27 at yahoo.com>
Sent: Friday, August 31, 2018 8:38 AM
To: Clayart International Pottery Discussion Forum
Subject: [Clayart] Snow Flake Crackle #4

I am working my way through testing John Britt's Snow Flake Crackle #4 glaze for Cone 6. Crackle is gorgeous, but it tends to have pin holes and craters, which are much worse on the back/bottom of test pieces. Why would this be?
I am careful with my bisque schedule to burn off organic materials and use an envirovent. Glaze may be a bit thinner on the back but the issue is more pronounced even if the glaze is the same thickness.
Have any of you succeeded with this? What firing schedule and clay body did you use? I contacted John and he used Brownstone from High Water in North Carolina. I would like to avoid shipping and can pick up clay easily in Portland, Tacoma, or Seattle.
Penny Berglund
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