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warping slabs and giffin gremlin

updated sat 22 nov 03


Barbara Kobler on fri 21 nov 03

Good afternoon all.
ABOUT THE GIFFIN GREMLIN; Several people have emailed and one named Jennifer made very nice comments about work on my website. I hit wrong key and lost my response. So thank you here. I will rectify the inability to enlarge the images hopefully in a week or so.

ABOUT WARPING AND SLAB WORK: Decided I can't resist putting in my two cents. Since 1979 all of my work has all been with slabs. I have not had any warpage at any time even with slab plates or 20" square flat pieces. That is unless I was doing something new and taking a chance. Like using a slab less than 1/8" thick on a curved 20" square. Duh. They didn't crack but only 3 out of 7 kept the curve. Yet I know that warping is the main problem for most of the people when they come in to my hand building slab working workshops.

Just a couple things: I use linoleum (paper side next to the clay) on top and bottom when rolling. I use both double roller and single roller slab rollers. I take 2 rolls back and forth at 1/4" incrememnts and always compress in-between rolls by slapping down the clay down with hands or a board. I always slide the linoleum supported clay directly onto a board from the slab roller for transport to work area. I never never ever transport unsupported clay. I never turn over a slab of clay without a sandwich of board,newspaper,clay,newspaper,board.

If I accidentally drop the clay or it gets banged. Then I always bang or redrop it in the opposite direction and vice versa several times before banging, slapping and turning it several times on the slab roller before rerolling. I have not wedged in 15 years. Never. Hurts too much. Just slap and bang. Just make sure you do both directions and both sides. And the last one is bang couple times each side.

I regularly use techniques I learned from Bill Daley to build working supports for slabs using roofing tar paper, builders styrofoam, hot glue gun, carboard, wood, nails and hammer. Think of the tarpaper as fabric and cut darts and seams and attached them together with a hot glue gun. Also regularly have used builders foam (not crumly type) sticking pieces rogether with wooden skewyers, shaping with a sure saver blade to get the form I want. If you construct a free form shape out of tar paper that has does not sit flat on a table then you have to construct a base and a frame around it. This is very crude. Use a piece of plywood for the base. Make a wall out of stiff cardboard 4" higher than the bottom of your tar paper shape. Attach the wall to the base with hot glue. Now you make lots of teeny 2" balls of newspaper and stuff them in the bottom, nestle your form in there and continue to stuff these small balls along the walls under your shape. This will now provide a good sup
port for up to 1" thick slabs. To turn over you will need a parter to help you invert it into another container so you can work on the other side and attache feet or whatever.

It sounds very complicated when written out but it's not.

I fire to cone 5-6 and use commercial clay: Laguna 52 plain clay 3/8" to 1" thick and Biz Bod paperclay usually a little less than 1/4".

FOR REGULAR CLAY I keep completely covered for 3 days if thick then do a standard slow dry--(1-4 months if thick and flat. If 1" thick then I candle for 2-3 days when bisque firing. FOR PAPER CLAY I dry in sun immediately unless it is a flat piece. If flat I keep covered 24 hours, uncovered indoor 1 day then outdoor in sun. I bisque fire pclay medium or fast.

Barbara Kobler