Barbara Kobler on sat 1 nov 03
Have been using pclay for 4 years and Biz Bod pclay from Mile High for about 6 months. I only fired bizbod pclay to 08 and after terra sig burnishing saggar to 1750. Previously I used about 2000 lb of Axners
sculpture pclay and fired it all to ^5.
With the last shipment of mile hi biz bod pclay, (in August) I have found an unusual and excessive number of air pockets and fissures in the clay as it comes out of the bag and even after going through slam bang and being put through a slab roller, it has had a gawd awful number of tiny air pockets which take considerable (a heck of a lot) time and effort to get rid of. My firings have been okay at this low temperature. But if you are having the same excessive air pockets in the pugged block and they are not completely removed that could be causing the burst.
Sometimes on pclay it is difficult to see or feel these small air bubbles especially when hand building with slabs. It is also difficult to get a really glassy smooth surface on pclay in general. If, when you slab pclay, roll it between the paper backing side of 2 pieces of linoleum. It will roll fairly smooth to begin with.
The key though is to: Wet down the slab with a handful of water, wet down a smooth metal piece of pipe and draw it across the slab to compress it and make the platlets (sp) lay down smooth. Don't roll the pipe as you do to thin or stretch the clay. Simply hold it down and pull it. If the metal pipe pulls or drags it means the clay and/or pipe is too dry. Run you hand across and rewet the pipe and/or slab. The result will be an exceptionally smooth surface. Especially for pclay and you then clearly see any air bubbles beneath the surface. (Metal has the lowest friction and accomplishes this very fine smoothness with pclay, or any clay, but you will not get this extra smooth effect with a plastic or wood roller)
You can email me direct if you
Barbara Kobler http://www.claywoman.net
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