TribeCreations Posted January 18, 2016 Report Share Posted January 18, 2016 Can I ask another question please Min? What clay do you use to make your bowls? I'm having endless issues trying to find the right clay body that will hold up without slumping/warping. Do you have any 'slumping/warping' issues with your bowls at all? Link to comment Share on other sites More sharing options...
Min Posted January 18, 2016 Report Share Posted January 18, 2016 Can I ask another question please Min? What clay do you use to make your bowls? I'm having endless issues trying to find the right clay body that will hold up without slumping/warping. Do you have any 'slumping/warping' issues with your bowls at all? I've used a few different clays for yarn bowls. I can't remember which one for the bowls in this thread but it would have been one of these two: Plainsman 370 http://plainsmanclays.com/index.php?menupath=8/29 or Glacier Porcelain http://www.clayartcenter.net/~clayar5/content/index.php?main_page=product_info&cPath=35_92_97&products_id=9576 they are pretty similar, ^6 smooth claybodies. Yup, I do get some warping. If I see any warping while they are drying they get tossed into the recycle bucket. Right now I would guess I have about 1 in 30 warp. Some do warp a bit in the glaze firing but not enough to worry about. I don't make the cat tail cut out very big and I think that really helps avoid warping. If I was having your problems I would make a couple test bowls, throw one with the walls a bit thicker than the other one, cut out the cat tail bit on a couple places in each bowl in different styles and fire them without bothering to underglaze or glaze them. See which cut out causes the least problems with warping and go from there. Also, if your glazes can go to ^5 1/2, which they should be able to, then I would consider slightly underfiring the y.bowls. Hope this helps and good luck! Link to comment Share on other sites More sharing options...
Chilly Posted January 18, 2016 Report Share Posted January 18, 2016 Why fire so high? Would ^06 glazes not give as good a result? Link to comment Share on other sites More sharing options...
TribeCreations Posted January 18, 2016 Report Share Posted January 18, 2016 Thanks a ton Min - much appreciated. The bowls keep their shape even after I have carved them in their leather hard state, and even before they are bisque fired - none warp in the bisque firing. It's only in the glaze firing that they warp, which I can only presume its because of the high heat. I will run a few tests at different temps to see which works best. I read something today and it made total sense: "As anyone who has worked with clay for a while knows, a method that works for one potter, may not work for another". That pretty much sums it up! Chilly: ^06 glazes will give a good result ... I just fire to ^6 because I use stoneware clay and ^6 glaze. I think I should lower the temp and see what the result it. The thing is; I'm told that stoneware clay matures at 1230Ëšc to 1300Ëš and if I fire under that threshold, then the clay won't be properly vitrified - if that makes any sense! Link to comment Share on other sites More sharing options...
bciskepottery Posted January 18, 2016 Report Share Posted January 18, 2016 I just fire to ^6 because I use stoneware clay and ^6 glaze. I think I should lower the temp and see what the result it. The thing is; I'm told that stoneware clay matures at 1230Ëšc to 1300Ëš and if I fire under that threshold, then the clay won't be properly vitrified - if that makes any sense! Firing to maturity (or vitrified) temperature makes absolute sense for functional ware; you don't want your vase seeping water. Knitting bowls are not functional ware in the sense they need to be fired to maturity to hold water or liquids. Glaze firing to a lower temperature will reduce the likelihood of warping. The only downside is the lower fired clay will not have the hardness of clay fired to vitrification. But, for knitting bowls, your stoneware glazed at low fire temps might be the solution. Link to comment Share on other sites More sharing options...
TribeCreations Posted January 19, 2016 Report Share Posted January 19, 2016 I just fire to ^6 because I use stoneware clay and ^6 glaze. I think I should lower the temp and see what the result it. The thing is; I'm told that stoneware clay matures at 1230Ëšc to 1300Ëš and if I fire under that threshold, then the clay won't be properly vitrified - if that makes any sense! Firing to maturity (or vitrified) temperature makes absolute sense for functional ware; you don't want your vase seeping water. Knitting bowls are not functional ware in the sense they need to be fired to maturity to hold water or liquids. Glaze firing to a lower temperature will reduce the likelihood of warping. The only downside is the lower fired clay will not have the hardness of clay fired to vitrification. But, for knitting bowls, your stoneware glazed at low fire temps might be the solution. Yes, good point - I never thought of it like that before. I will try a lower temp and do some tests to see which method works best. Thanks for your input. Link to comment Share on other sites More sharing options...
RoGryphon Posted January 19, 2016 Report Share Posted January 19, 2016 I have been doing yarn bowls also. Sold out of them at xmas. Since they are nice and thick great for a newbie potter. I dry upside down but do like the idea of leaving a bit at the top, will try that with next batch. I use a stoneware clay and fire to ^5 since I also am trying mugs and don't want to have two sets of clay/glaze. I tried a little loafers for some bowls and it just broke when I tried smoothing the edges etc, to dainty I suppose. Fun item to make. Link to comment Share on other sites More sharing options...
TribeCreations Posted January 19, 2016 Report Share Posted January 19, 2016 I have been doing yarn bowls also. Sold out of them at xmas. Since they are nice and thick great for a newbie potter. I dry upside down but do like the idea of leaving a bit at the top, will try that with next batch. I use a stoneware clay and fire to ^5 since I also am trying mugs and don't want to have two sets of clay/glaze. I tried a little loafers for some bowls and it just broke when I tried smoothing the edges etc, to dainty I suppose. Fun item to make. Oh WOW ... those yarn bowls look stunning! I think I'm being too extravagant with the cut-out design, but in saying that, there is a woman who makes similar one's and her's come out fine - no issues what-so-ever. Go figure! I also dry my bowls upside down, and only carve the shape out when its leather hard. I leave a bit on the top and middle to act as 'supports' as clay has a memory. When it's really bone dry, I remove those supports; or depending on the cut-out design, I bisque fire them with the 'supports' in and just grind down the bits with a tool - very time consuming though. Link to comment Share on other sites More sharing options...
Joy pots Posted January 19, 2016 Report Share Posted January 19, 2016 Try laying a piece of newspaper on top while drying. It helps to keep pieces from warping while drying. Link to comment Share on other sites More sharing options...
Jo-Ann Posted January 19, 2016 Report Share Posted January 19, 2016 Yarn bowls are my absolute favourite to make, I enjoy making each one different depending on my mood. I use stonewear clay, throw a little thicker and cut just before leather hard. I wrap the top in plastic and dry upside down. Sometimes I will use paper wedges to support the swirl part if I notice some sagging (the wedges just burn up in the kiln) after I bisque I sand the swirl as I once used a yarn bowl that didn't have a perfectly smooth swirl and it snagged my yarn and really annoyed me while I was knitting lol so now i'm mindful of how smooth the swirl and inner bowl is. I use a small sharp blade and hand carve all of my cuts, which is why I cut just before leather hard, I find that while there is risk of sagging for me its easier to carve when the clay isn't so stiff. Yarn bowls are my biggest seller. I personally don't like, wont use and wont sell a warped bowl but that's just me being picky. Slow drying, a gentle hand when carving and paper wedges for support helps me avoid warping. Here are a bunch of bowls i've made. Link to comment Share on other sites More sharing options...
TribeCreations Posted January 21, 2016 Report Share Posted January 21, 2016 Yarn bowls are my absolute favourite to make, I enjoy making each one different depending on my mood. I use stonewear clay, throw a little thicker and cut just before leather hard. I wrap the top in plastic and dry upside down. Sometimes I will use paper wedges to support the swirl part if I notice some sagging (the wedges just burn up in the kiln) after I bisque I sand the swirl as I once used a yarn bowl that didn't have a perfectly smooth swirl and it snagged my yarn and really annoyed me while I was knitting lol so now i'm mindful of how smooth the swirl and inner bowl is. I use a small sharp blade and hand carve all of my cuts, which is why I cut just before leather hard, I find that while there is risk of sagging for me its easier to carve when the clay isn't so stiff. Yarn bowls are my biggest seller. I personally don't like, wont use and wont sell a warped bowl but that's just me being picky. Slow drying, a gentle hand when carving and paper wedges for support helps me avoid warping. Here are a bunch of bowls i've made. WOW ... those bowls are simply stunning Jo-Ann. I see you also take a generous amount away (cut/carve out) as I do. Do you have many that slump/warp after firing? What's the top temperature you fire these babies to in your glaze firing? They truly are quite beautiful. Link to comment Share on other sites More sharing options...
Jo-Ann Posted January 24, 2016 Report Share Posted January 24, 2016 Yarn bowls are my absolute favourite to make, I enjoy making each one different depending on my mood. I use stonewear clay, throw a little thicker and cut just before leather hard. I wrap the top in plastic and dry upside down. Sometimes I will use paper wedges to support the swirl part if I notice some sagging (the wedges just burn up in the kiln) after I bisque I sand the swirl as I once used a yarn bowl that didn't have a perfectly smooth swirl and it snagged my yarn and really annoyed me while I was knitting lol so now i'm mindful of how smooth the swirl and inner bowl is. I use a small sharp blade and hand carve all of my cuts, which is why I cut just before leather hard, I find that while there is risk of sagging for me its easier to carve when the clay isn't so stiff. Yarn bowls are my biggest seller. I personally don't like, wont use and wont sell a warped bowl but that's just me being picky. Slow drying, a gentle hand when carving and paper wedges for support helps me avoid warping. Here are a bunch of bowls i've made. WOW ... those bowls are simply stunning Jo-Ann. I see you also take a generous amount away (cut/carve out) as I do. Do you have many that slump/warp after firing? What's the top temperature you fire these babies to in your glaze firing? They truly are quite beautiful. thank you so much for your kind words on my work my fire schedule is probably overly slow but it seems to be working for me, i have about 2 warped bowls of every 20 the warps aren't as dramatic as when i used to fire quicker. I opened my kill this morning and can show you what a warp looks like after i get a photo. My fire schedules are as fallows Bisque to cone 06 (900 to 1000 degrees celsius I have a manual kiln and no temp gauge so its not exact, I trust in the cone lol) - 3 hours all switches on low, all peeps open, lid propped open - 1 hour all switches on medium, all peeps open, lid propped open - 2 hours all switches on medium, all peeps in except the top two, lid closed - until sitter shuts off (usually about 2-3 hours) all switches on high, all peeps in, lid closed I allow 20 hours too cool before opening, keeping my down draft vent running and removing all peeps around the half way point Glaze fire to cone 6 (1200 to 1300 degrees celsius) - 2 hours all switches on low setting, all peeps open, lid propped open - 3 hours all switches on low, all peeps in except the top two, lid closed - 3 hours all switches on medium, all peeps in except the top two, lid closed - 2 hour all switches on medium, all peeps in, lid closed - until sitter shuts off (usually about 2 hours) all switches on high, all peeps in, lid closed I allow 24 hours too cool before opening, keeping my down draft vent running and removing all peeps around the half way point Link to comment Share on other sites More sharing options...
Jo-Ann Posted January 27, 2016 Report Share Posted January 27, 2016 sorry its take so long, I'm retiring from my government job this week so things have been crazy! Anyway, as promised here is an example of how small the warping is when my bowls do warp. Its rarely worse than this. Link to comment Share on other sites More sharing options...
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