Tyler Miller Posted January 4, 2014 Report Share Posted January 4, 2014 Hello, I've been a lurker on this forum for a long time. Your discussions have been a great help whenever I've had questions about what I'm doing. Thank you guys for that. The reason I'm posting is this youtube video on Onggi a friend sent me: http://www.youtube.com/watch?v=6p57x0g1WfE&feature=youtu.be Specifically 3:10. They say the glaze is composed of ash and leaf mold made from decomposed autumn leaves. I had a million questions. Is the leaf mold used as is? If so, is the loss on ignition great? Is it turned to ash? what species of leaves are they? What is it doing chemically? Is it misinformation? The best information about leaf mold I could come up with came from a gardening manual, which said it was used for its potash and phosphate content in soil amendment I'd love to know more, if anyone has any experience with glazes made with leaf mold. This little fact has changed completely what I though glazes could be. Link to comment Share on other sites More sharing options...
bciskepottery Posted January 4, 2014 Report Share Posted January 4, 2014 Fascinating video; thanks for posting. It sounds as though they allow mountain leaves to mold and decompose, then grind them into a powder that is mixed with wood ash and water into a slip-glaze. Plus, you are getting some ash from the wood firing that will help glaze the onggi. Some feldspars are potash feldspars, so that would be consistent with glaze materials we are familiar with -- probably much the same a using peat as a fuel. In some low fire and pit fire practices, people add fertilizers (Miracle Gro) to add colors, effects -- and those are made of potash, phosphates, etc. My guess is they harvest particular leaves from mountain trees to make the leaf mold. Link to comment Share on other sites More sharing options...
Bob Coyle Posted January 5, 2014 Report Share Posted January 5, 2014 The wood ash should have pretty much the same minerals as the leaf mold. The difference is the the leaf mold contains acidic tannins which might help with the consistency of the glaze and also serve as a binder sort of like CMC. This is just a guess though. I'll let those more knowledgeable in Oriental ceramics weigh in. Link to comment Share on other sites More sharing options...
Biglou13 Posted January 5, 2014 Report Share Posted January 5, 2014 Tyler welcome Great post Great video Let us/me know if you start experimenting with glaze. And if you get more info. I imagine one/some of our resident jedi's (Experts) will chime in soon. As a woodfired fan (atic). It's amazing that woodfired pottery looks great but even more so it contributes to life saving anti carcinogenic properties! I have few pieces woodfired pieces that I use, now even more anxious for more. No experience with leaf mould but am fascinated. Is it truly a 2 part glaze? Also what kind of wood ash? Next variable is clay? Next is what kind of wood used in firing? I'm currently dabbling with ash based glaze. I really like the idea and addition of organic component. Link to comment Share on other sites More sharing options...
bciskepottery Posted January 5, 2014 Report Share Posted January 5, 2014 Google can be your best friend . . . The Smithsonian has published a study http://www.sil.si.edu/smithsoniancontributions/Folklife/pdf_lo/SCFS-0005.pdf (caution: big PDF file). http://yesanonggi.koreasme.com/en/sub_01_01.html http://www.koreanonggi.com/True_Character.html Clay bodies and glazes seem to vary from different areas, but there are common traits: low fire earthenware, slip-glaze made of clay body, ash, sometimes manganese, -- but left for 6 or more months before being used. Enjoy. Link to comment Share on other sites More sharing options...
Tyler Miller Posted January 5, 2014 Author Report Share Posted January 5, 2014 Bob, I'm inclined to agree with you about the leaf mold. But would that mean its presence is very small percentage of the recipe, like CMC? Biglou, I intend to explore these glazes at my earliest opportunity. bciskepottery, thanks for posting that Smithsonian study. I had seen the other two sites before, but I've never come across that pdf. It will make excellent reading over the next while. I was aware that ash and clay glazes were used, but I didn't know much about their preparation and use. I'm surprised they fired to such low temperatures, it seems like cone 1-4 is about the maximum range. Link to comment Share on other sites More sharing options...
Guest JBaymore Posted January 5, 2014 Report Share Posted January 5, 2014 In Japan when we've had Korean Onggi potters come and work with us there, sometimes we've put some of their onggi clay in the typical anagama or noborigama firings there....... and turned them into mis-shapen, warping, slumping twisted forms. The onggi clay is a very high iron and high impurity (flux) bearing material. GREAT ro work with, but much lower firing than we assume here in the West. best, ..........................john Link to comment Share on other sites More sharing options...
RuthB Posted January 5, 2014 Report Share Posted January 5, 2014 Wow! Great film. I was fortunate to see Mr. Oh make Onggi at the International Ceramics Festival in Aberystwyth a couple of years ago. The close ups of adding the coil in this film are great. The idea of using leaf mold in a glaze is very interesting. I wonder what other decomposed organics would do? Where can I get an Onggi hat? Ruth Ballou Charleston, SC Link to comment Share on other sites More sharing options...
bciskepottery Posted January 5, 2014 Report Share Posted January 5, 2014 bciskepottery, thanks for posting that Smithsonian study. I had seen the other two sites before, but I've never come across that pdf. It will make excellent reading over the next while. I was aware that ash and clay glazes were used, but I didn't know much about their preparation and use. I'm surprised they fired to such low temperatures, it seems like cone 1-4 is about the maximum range. It seems as if low-fire is necessary for the onggi functionality . . . namely, being porous enough to allow fermentation of soy sauce, kimshi, etc., and to allow storage of dry foods such as rice and to promote the growth of antacids. Fired to stoneware or higher temps would vitrify the clay too much. That is what I've found so fascinating about this . . . I always thought onggi was just a form and way of making large containers, but it is also about the tie between making and the materials used for making to a specific functionality and use. Link to comment Share on other sites More sharing options...
bciskepottery Posted January 5, 2014 Report Share Posted January 5, 2014 Here is a link to a similar project, but based on jars made in Thailand. But the method of making is the same. These are fired higher in temperature, though. http://danieljohnstonpottery.com/large-jar-project/ Link to comment Share on other sites More sharing options...
Guest JBaymore Posted January 5, 2014 Report Share Posted January 5, 2014 That is what I've found so fascinating about this . . . I always thought onggi was just a form and way of making large containers, but it is also about the tie between making and the materials used for making to a specific functionality and use. When you get a chance to travel to Japan, Korea, and China, you realize that there is a "culture" circulating around abd through the particular ceramic wares production that goes way beyond what most of us westerners tend to percieve from afar. best, ....................john Link to comment Share on other sites More sharing options...
Tyler Miller Posted January 6, 2014 Author Report Share Posted January 6, 2014 John, I think Korea might be exceptional in its ceramic culture. Shoji Hamada said (in Leach's Hamada Potter) that Korean pottery was closest to its people, maybe not the finest pottery, but closest to its people and their culture (to brutally paraphrase). In my experience with it, this is absolutely true. Perhaps its my ignorance of eastern ceramic culture, but I can't think of any parallels to what goes on in Korea. Link to comment Share on other sites More sharing options...
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