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WoodlandPotter

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  1. Help my slabs are cracking up

    Hi Julia, Sorry, no. I have no experience using silica sand, I am afraid. I simply bisque fire my tiles flat on the shelves and stilt them in the glaze firing. I haven't had any problems. I would have looked for a solution had I seen cracks, or splits, or whatever, but no... all have come out fine. Maybe I've been lucky. I don't know. I have made some large, but to be fair most have been small tiles, 5 inches by 5 inches, or 5 inches by 7 inches. Maybe that's the reason I haven't run into any problems with them. Hmm.... I wonder if the following makes a difference: When making tiles, I use the technique I learned when I was a kid from a potter who railed that the only correct way to create slabs was to throw them. It involves throwing a flattened ball of well kneaded clay down on a piece of cardboard at an angle. The bottom part of the clay will grab on the surface, while the top part of the clay will stretch in the direction of the throw. It's reminiscent of the way a pizzeria cook stretches pizza dough, only in the case of clay, it is stretched by throwing it down, lifting it off, turning it and throwing it down again, repeatedly until the slab is the desired thickness. I have been practicing this since I was ten, so it's easier for me to make slabs this way, than any other way. Maybe the tiles I cut from these slabs are more resistant to cracking because having been stretched, most of the clay particles lay in the same direction. I don't know. It's an idea.
  2. Help my slabs are cracking up

    Hi Julia, I have done a lot of the sort of work you are attempting. In my case, nearly all commission work with hard deadlines. Lots of pots and/ or tiles with sprig (2D relief) work on them. So I know. Always pressed for time, seemingly. Racing to get things made, so they can dry as slowly, and as completely, as they need. In this regard, I find myself throwing pots, or making tiles and then when they are barely stiff enough to be handled, pressing and pulling out the sprigs from the molds and applying them on to the pots, or tiles when everything is still quite wet. I use a wire brush and score both sprig bottom and ware body. I make two passes of scores, at right angles of each other. Dabbing a drop of water into the score on the ware, to displace air bubbles and to help further seal the bond, I will then place the sprig on. Then, this is important, I always wipe my fingers, quickly, and try to get them as dry as I can. I found that pressing the soft wet clay sprig on to the pot does very little deforming if the fingers I am using to press with are dry. Try it. As for thick sprigs, especially on pots that can’t have pin holes through their bodies, stabbing with a pin tool into the sides of the sprig, parallel to the plane of the tile, or pot, but not into the area of the scored bond, works great and allows it to out gas any residual moisture just fine. These deadlines, they are sometimes a beast! I have been known to sprig 40 pots in a sitting. Knock on wood, I have only had three sprigs ever come off and one blown off, and that out of thousands of pots and tiles. At the time, I noted that friends don’t let friends sprig at 3 am in the morning. I got sloppy and didn’t score with my usual care. Anyway, those particular pots were fired artfully tipped over enough to, I hoped, to keep the sprigs from sliding and I did succeed in fusing the sprigs back on in the glaze fire. And, I made deadline, got paid, and all is well. Best wishes that everything goes well for you and you make deadline. -Charlotte
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