Rex Johnson Posted September 4, 2015 Report Share Posted September 4, 2015 I'm making some 16" wide and shallow bowls. Talk about wanting to warp, but that's normal. Since these are made on a hump mold, it's nice because I don't need to trim. The foot is thrown and compressed and therefore pretty much symmetrical . When they are leather hard I can flip over and dress the rim. I let it sit for 30 minutes then dry rim down overnight, covered with a thin trashcan liner on my ware shelf which is wrapped in plastic. Next day I remove the thin plastic test the foot for flatness on a marble countertop wedging table. From there I'll set it up right. Note that my studio is outside and I live in the SoCal desert, so I have to pay attention to stuff like this. Another thing I do if I have concern about warping or the foot not being flat is to place a bat on the foot when it's flip on the rim... In other words, the opposite of this pic ... Link to comment Share on other sites More sharing options...
Mark C. Posted September 4, 2015 Report Share Posted September 4, 2015 Porcelain drys so fast I seem to have less issues with it than I used to with stonewares. Mark Link to comment Share on other sites More sharing options...
kcompton@usitexas.com Posted September 4, 2015 Report Share Posted September 4, 2015 About the only good thing about the climate in the Houston area is that the humidity is so high that you don't have to worry much about really uneven drying on moderate-sized pieces. For the 3 or 4 low-humidity days we have every year one has to be more careful, and I do turn bowls over after a bit to even-out the drying, usually after trimming. My pots don't seem to have a strong opinion about the whole thing, though. Link to comment Share on other sites More sharing options...
Joseph Fireborn Posted September 4, 2015 Report Share Posted September 4, 2015 Porcelain dryings so fast I seem to have less issues with it thanI used to with stonewares. Mark Thats how I feel. When I throw porcelain its ready to handle or trim in like 3 hours. Link to comment Share on other sites More sharing options...
alabama Posted September 7, 2015 Report Share Posted September 7, 2015 ###Does anyone have an idea why a crack would develop in a foot ring on a bowl? The crack didn't show until it was glaze fired.### Hey, There isn't mentioned the size/weight of the bowl...but if it only happened once, it could just a fluke. If it happens again, I might try leaving vessels upside down on the bat and moving the bat and bowl together. I might try turning the vessels upside down in another manner...instead of manhandling vessels, place a bat over the rim then with enough pressure flip both bats with the vessel sandwiched between the bats. You might consider the material the bats are drying on... As long as the vessel is damp, it is still shrinking, so where clean plastic bats might not allow movement a wooden or Masonite board will. Any stressed crack is one that only shows when bisqued/glazed fired. I think it's safe to say, we feel your pain, when something causes a crack and there isn't a obvious answer. Just for giggles check the amount of grog in your clay, it might be the clay body, if it happens often. In most of my cases where cracks appear for no apparent reasons, its always due to making something for a specific person. Putting "to and from" on the bottom of any vessel I make is a kiss of death, so I have to put a to and from hang tag or sticker on the vessel to keep it from cracking. I'm not superstitious, but that works for me. I seldom make pottery on "Friday the 13th"... This month Friday the 13th falls on next Sunday, so I might not throw or trim on that day, but will throw a pinch of salt over my left shoulder. :-) See ya, Alabama Link to comment Share on other sites More sharing options...
nativesilver Posted October 14, 2015 Report Share Posted October 14, 2015 I have a similar question to this in regards to firing. I've made some hanging planters, basically a bowl that I've fully rounded the bottom of and added a decorative knob. Since there is no flat surface or foot on the bottom I've had to dry them in their rims. I've also fired them this way but some have come out of the glaze fire with the rim distorted. I'm guessing this has to do with the weight of the pot and the expanding and contracting while in the kiln. Does any one have an alternative suggestion for a way to fire these. My thoughts include on their sides on stilts (not my favorite idea b/c of marks), resting on a kiln post from the inside so that the pots are lifted slightly off the shelf or on a biscuit so that the surface and the rim expand/ contract at the same rate. If anyone has any experience with something like this I'd love to know your thoughts on the matter. Many Thanks! Link to comment Share on other sites More sharing options...
Mark C. Posted October 14, 2015 Report Share Posted October 14, 2015 I have a similar question to this in regards to firing. I've made some hanging planters, basically a bowl that I've fully rounded the bottom of and added a decorative knob. Since there is no flat surface or foot on the bottom I've had to dry them in their rims. I've also fired them this way but some have come out of the glaze fire with the rim distorted. I'm guessing this has to do with the weight of the pot and the expanding and contracting while in the kiln. Does any one have an alternative suggestion for a way to fire these. My thoughts include on their sides on stilts (not my favorite idea b/c of marks), resting on a kiln post from the inside so that the pots are lifted slightly off the shelf or on a biscuit so that the surface and the rim expand/ contract at the same rate. If anyone has any experience with something like this I'd love to know your thoughts on the matter. Many Thanks! Your rims are shrinking during a glaze fire-hence the distortion To fix this fre them on a thin waster slab of same clay body which will shrink the same. Mark Link to comment Share on other sites More sharing options...
oldlady Posted October 15, 2015 Report Share Posted October 15, 2015 have fired some upside down on a post. no warping. Link to comment Share on other sites More sharing options...
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