[Clayart] Mica question for Snail and other mica info.
Vince Pitelka via Clayart
clayart at lists.clayartworld.com
Sat Aug 30 07:42:42 EDT 2014
Gina Mars wrote:
"Hi All and Snail, I have read most of the mica posts and I was wondering About the part when you said put on the terra sig and fire it and then apply It again after bisque. I have rarely used it and thought you really need to burnish a piece And bisque it. I thought the terra sig would not work after it's bisqued?"
Hi Gina -
Applying terra sig to bisqueware is always a little precarious, and even with a thin layer it often chips/peels. Applying it to bisqueware is odd, since it's so much more effective to apply it to dry greenware. Applying it to damp or leather-hard greenware is risky because the polished terra sig finish has very little capacity for shrinkage and crinkles on a microscopic level as the piece dries, disrupting the shine.
I hope this doesn't sound picky, but if you have to burnish it to get a shine, then it's not a real terra sig. Burnishing implies polishing by compressing/rubbing the surface with a hard, smooth, unyielding object like a shiny stone or the back of a spoon, and of course you can get a shine on any claybody by doing that. A good terra sig can be polished to a high shine with a piece of grocery bag plastic, a soft brush, or a very soft piece of chamois - anything that gets the particles to lay flat and reflect light. So much of the way terra sig behaves depends on whether or not it has been properly prepared. I certainly don't claim to have come with the best terra sig recipe, but I regularly get positive feedback from people who love it. For anyone interested, my terra sig article is on my website (link below).
Appalachian Center for Craft
Tennessee Tech University
vpitelka at dtccom.net
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