How to Dry Clay Sculpture
Recent Q&A: How to program a glass flash-cooling in a digital kiln
Announcement: Ed and Martha Biggar's October Glass and PMC Classes in Dallas, Texas
HOW TO DRY CLAY SCULPTURE
By Carole Dwinell
To keep clay workable and 'wet,' I use clear 33-gallon garbage bags that I get at Costco. They must be clear so you can see the moisture on the plastic as water starts to evaporate. You want to know that the air inside the bag stays moist.
Place the ware on a piece of 100 lb. card stock (about the thickness of a business card and sold by paper companies). I have a ream of it in my studio. I used to use newspaper, but it shreds.
Place the ware, which is on the sheet of 100 lb. card stock, on a scrap piece of plastic (which I get from Tap Plastics). Keep the whole thing inside the clear garbage bag secured VERY tightly by twisting and twisting the opening of the bag. Then wrap the twisted plastic with a really strong rubber band.
I open the bag and spray the piece almost daily to keep the air in the bag saturated with humidity. That way I can work on the piece for many months.
When I'm finished with the clay sculpture and I want to start drying it, I open the bag for maybe 20 minutes. Then I twist and band it shut really tight again. Over a week or two, depending on the complexity of the clay piece, I gradually increase the time that I leave the bag open. I'll leave it open 30 minutes, then 45, then an hour and so on before totally sealing it off again.
The work I'm doing now includes thick tree trunks and very thin leaves. The tree sculptures are tricky because the leaves always try to dry first. By controlling the amount of time I expose the clay to drier air, those leaves become the conduit for the moisture in the rest of the clay to reach the surface.
By slowing the drying, the drier clay on the edges has time to pull the moisture from the thicker parts of the piece. With clay platters, the edges probably dry first. The foot and surrounding area are the last to dry. That's where the stress comes in. That's what used to happen with my thrown stuff, but since I started using the above drying method, I have had no cracks, no breaks, no shearing, nada, nothing. (Well, once I bumped a piece, but that doesn't count, does it?)
Remember that this drying procedure accompanies the 46 hour 'up' and 36 hour 'down' bisque firing. Both are crucial to the 'no breakage' success story. I have NO breakage at all.
(Carole’s article “A Firing Schedule for Clay Sculpture” appears as the 05/15/2007 Kiln Pointer.
“A Firing Schedule for Clay Sculpture”
Q. Will programming a FULL rate during a cooling segment turn off the elements?
A. Yes. If you will be raising the lid to flash-cool the glass after the glass has fused, you should program a FULL rate. This turns off the elements during that segment so the kiln can cool quickly.
ANNOUNCEMENT: ED AND MARTHA BIGGAR GLASS AND PMC CLASSES AT THE CREATIVE ARTS CENTER, DALLAS, TEXAS, OCTOBER 2007
Thursday, October 11: New Techniques in Fused Glass. This beginner to intermediate class will include several new techniques in kilnforming: liquid stringer, glass paper inclusions, and simple pate de vere, among others.
Friday, October 12: Beginning PMC. Students will learn the basics of PMC while making at least three pairs of earrings and two pendants.
Saturday, October 13 and Sunday October 14: Intermediate PMC. This class is for the person who’s had a little experience with metal clay but wants to push the envelope in their design and fabrication work.
For more information and to register, call Ed at 276-620-8595, Or visit www.edandmarthabiggar.com .
Ed and Martha Biggar
With best wishes,
Arnold Howard Paragon Industries, L.P. – Better Designed Kilns 2011 South Town East Blvd. Mesquite, TX 75149-1122 Voice: 972-288-7557 & 800-876-4328 / Fax: 972-222-0646 firstname.lastname@example.org / www.paragonweb.com
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