Interior Supports? sculpture integrity
Posted 11 October 2010 - 09:26 PM
Posted 12 October 2010 - 12:09 AM
I understand your concerns.
What cone are you planning to fire your piece to? For the work that I do (almost all sculptural), cone 5 works nicely. My taller pieces shrink more at Cone 10 and are subjected to more unnecessary stress in the firing. So if you can do Cone 5 or even lower, that's one option to get less slumping.
I assume you are using a traditional clay body. Your 1/2 " slabs are pretty substantial. I don't know if additional internal supports will help since this will increase the weight even more. However, if you are planning to incorporate internal struts, I would recommend a hollow tube form. Think of it as a hollow pipe and using this as an internal armature.
Have you thought of using paper clay for your tall pieces?
Hope this helps
Posted 12 October 2010 - 08:53 AM
Cones and cylinders are strong forms. Could it be possible you were building before the lower parts were set up enough to withstand the weight? Sometimes if you add too much too quickly, the wet clay can't take it but stiffer clay could.
I agree with Anthony that paper clay or a clay with nylon fibers may be a benefit for what you are trying to do. Meanwhile you can patch the crack with a paperclay patch. Let is set up. Try a heat gun on the lower part to speed up the process and keep a wet rag on the edge you need to add to.
Posted 13 October 2010 - 01:19 PM
I have used two methods: (1) for a 46" tall figure .... I made a beanbag form in the rough shape of my standing figure and suspended it from a beam in my studio. The figure was worked in 1.5" coils around it and the beanbag armature worked a treat. As the clay dried, the beans could expand into the area left at the top and when the whole thing was stiff enough to self-support, I opened the top of the beanbag and extracted the beans with a vacuum cleaner - it filled the cleaner a few times! I then completed and closed the sculpture. I too had to cut the figure in half for firing - I used fine piano wire, held very taut by me and a friend whilst another friend supported the work. On the whole it worked very well, but I would advise trying to find a "natural" join, as I can still see the join in my sculpture - friends tell me I'm picky!
(2) for a 3ft tall crouching figure .... again using 1.5" coils, I built two intersecting internal walls whilst building the form and this worked very well, but I had the inside space to do it. I've also used rolled up cardboard strips (the sort with one wavy side) which cope well with shrinkage and burn off in firing
I do hope this helps and wish you success with your sculpture
Posted 14 October 2010 - 07:20 PM
Posted 15 October 2010 - 06:51 AM
Posted 16 October 2010 - 08:42 AM
Thanks; I'd be interested in seeing that. My studio, despite being in NOLA, dries my clay out quickly, so I'm constantly spraying slabs and pieces. I've got the parts for the current piece wrapped in 5 plastic bags, with damp cloth on that, and it's still iffy. It makes smaller pieces tempting.