Limestone and Cedar

  • Studio on Wheels

    I have a friend who is a boat builder, and I was in his shop when I noticed he was able to move around all of the work benches and equipment. He had attached small wheels to the bottom of everything. This made it really easy to have a very versatile space; it was easy to clean up, it creates more space and it saves you from pushing around heavy equipment.
    So I decided to do that in my studio – it works beautifully!
  • Wooden Spoons Book

    I spoke in a previous post about making wooden spoons. Well, I came across this Japanese book about carving spoons and its great. This kind of thing is something that the Japanese do so well. Despite living in the most high tech society, the Japanese seemingly still have a great connection to the origins of craft.
    I love the economy of his working space.
  • Wood Firing Kiln

    This kiln is a two chamber wood burning kiln built in 2001 by Donovan Palmquest. It is located in Northern Indiana. Its a pretty big kiln for me so I fire only a few times a year. The last time I did a firing was last October; late fall and early spring are my favorite times to fire.
    A lot of potters take several days to fire, but my firing in this kiln was very short. We reached temperature in the first chamber in about 24 hours and then I took 6 more hours to fire the second chamber to cone 9. The second chamber can reach temperature in about half an hour, so I have to be very careful to go slowly to allow the glazes to mature and build depth.
    Unlike many potters, I choose to glaze most of the work because I`m interested in the effect of fly ash and flame on my natural ash glazes. Because there`s wood ash in my glaze already the fly ash blends in beautifully, making unpredictable variations that add a depth that`s not obtainable in a gas kiln. I especially like how the flame gives a warm tone to the exposed clay body. The bottoms of the pots are suspended by small wads of clay that are removed after the firing, this allows the flame to pass under them.I use the gas kiln for developing glazes and firing wares that would warp or distort when exposed to direct contact with flame. When I get the glaze to where I want it to be, I`ll use it in the wood kiln, and see what that adds to it.

    Right now I`m working on flat plates that are hand built on the wheel. they do a lot better in the gas kiln. I`ll post some pictures up here soon.

  • Wood Ash

    Wood ash needs to be washed many times to take the soluble material and the fluxus off, and then the material is screened and then dried. The rice husk ash is processed the same way; I wash it and then I pulverise it in a ball mill, to get it to pass through a 100 mesh screen. My brother heats his shop with wood, so there`s an abundance of ash around and I like using ash that way, as it`s something that people throw out. I also get my rice husk ash from powerplants that use rice husk for fuel; the ash is a byproduct. However you can`t buy directly from these people, they don`t want to be bothered by potters. You have to buy mountains of it; they want you to buy a truck load which is about 42000 pounds, so I had to purchase enough for a lifetime.

    I like learning about how to bring out the best in that material. Now, I`m not a wine maker but I imagine it`s a lot like that process, where they are trying to extract the highest quality product from the soil and the grape and that`s exactly what I want to do with my glaze materials. For years now I have been asking what is the best way to process rice husk ash? How fine do I have to grind it or leave it coarse, what do I have to blend it with and what kind of mesh do I use there? What kind of wood ash is best? I was fortunate enough to work with a fellow potter, Paul Wakenight, who happens to be a scientist. He was a huge help in setting up experiments and investigations from which I learnt a great deal, and the experience was invaluable.

    Here are some pictures of burning apple wood for ash:

  • Glazes

    For my glazes I`m using raw materials: wood ash, rice husk ash and a crushed stone feldspar and sometimes a little bit of my kalin. I like to keep the formulas as simple as possible. I try to emulate how glazes were made 300 years ago, and I use the Wilson book (Inside Japanese Ceramics) on glaze as a starting pointfor formulas. From there I adjust either wood ash, rice husk ash or feldspar to get the desired melt.

  • Feldspar

    Right now I get my feldspar in a super sack of over a 1000 pounds and it looks like cat litter.

    It comes out of North Dakota and it`s a blend of different veins. The reason why I get that is because it`s just pulverised rock; it hasn`t been washed, it hasn`t been de-ironed and they haven`t pulled out the impurities. It glistens with mika, pink granite, and obsidian. When you get a bag of commercial feldspar it`s gone through a lot of refining before it`s crushed and they crush it to a point where it`s 200 mesh or finer. That makes a particular kind of glaze that we are really used to looking at, it`s very uniform. Now, this makes a good glaze but I`m interested in what happens when you are not refining the feldspar as much. I started noticing this when I would study rice ash glazes at the Freer Sackler Museum.

    I use a Hammer Mill to take the coarse stone down to about a 60 mesh
    Then I use a Ball Mill to take materials from the 60 mesh downwards
    Drying feldspar after ball milling
    Finished feldspar – note the coarseness of the material
  • Feldspar in Clay

    I blend these clays without any feldspar addition to the body so that the body stays open, even at its peak temp at cone 10.

    I find this helps the pot to breathe more, it has a softness to it. I find the commercially made clay bodies that are loaded with feldspar are tight, they have reached a maturation point, a vitrification that makes them almost glass-like and I find clay like that doesn`t communicate its raw state to me; it`s been processed too far and something is lost in the in the firing process.

    I will not use feldspar unless I absolutely have to; for example if the glaze is spitting. I learned this from using Japanese pots, they sound different; if you tap them, they typically go thunk thunk, whereas a pot made here will typically go ting ting.

  • Commercial Clay

    I do use commercial clays but only now for small objects. I find that commercial bodies are formulated for plasticity and they have more feldspar in them and that`s ok, I think there`s a point at which that`s useful, but I really like working with material in its rawest state.

    Typically, I think you can find good clays that have plasticity, yet if you are using clays in their raw states, you may be faced with making compromises; maybe that plastic clay provides really great workability, but it might be a lousy colour, and you have to work with that, and I think thats a good thing. You let the material be what it is; if you are working with a clay that has character and you want to bring that character out all the way through, you`re going to be taking the back seat. I listen to the material, what will it do, what will it not do and it tells me straight away, and that to me is another level of engagement.

    I want to use a material that wont do everything I ask it to; I want a material that has something to say on its own and I work with it to bring it through. I think of it as a duet, or a dance.

  • Clay

    I work with two kinds of clays, a brick clay from Georgia and a very impure kalin from Montana.

    The Montana clay is called Helmar (on the right of the picture above) and is from a very small mine near the Archie Bray Foundation.
    I like its properties because it`s not a very clean kalin; it has a beautiful yellow tinge to it, so it makes a terrific slip because that warmth comes through.
    I like that quality compared to a refined English porcelain or grolleg which it is so white. Now, there`s an elegance to grolleg but there is something gutsy to the kalin from Montana.

    The other clay I`m using from Georgia is Lizella (on the left of the picture). I used to use Ocmulgee, which is a neighbor from the same area. Now the Lizella is not nearly as nice as the Ocmulgee, but it`s got some guts to it; it`s a tough clay to use, it kind of sucks up water, and it can be kind of mealy but it fires up beautifully in the wood kiln. I add kalin and fire clay to it to open it up and so it can go to higher temperatures.

    The clays come in 50 pound bags. I blend them in a dough mixer, and then I typically make a 1500 pound pile and I let it age. I mix it wet and let it sit for 8 months, after that its really quite nice, although a year is better.

  • Museum Experience

    Charles Jahn Pottery  Rice Husk Ash Glazes

    When I was fresh out of art school, and travelling alone in Japan, I visited the Mingei Kan, a folkcraft museum in Tokyo to check out their pottery collection. I came across a small display of a variety of handmade functional objects: cups, bowls, and small plates. Each piece was clearly made by a different maker and was the result of many different investigations and yet they shared the same visual language, they shared the same purpose (that of utility) and they complemented each other; there was a harmony among them.

    That was such a beautiful thing to me; in each one of those objects there was a lineage of a few generations figuring things out and passing on information as to how they got their patterns or how they processed their materials to end up with that fired end object. They were unique to their location and unique to their makers.

    That small display was so exciting, it introduced me to the subtleties of folk craft pottery.

    I like to have that diversity at home on my table. Here are 3 pots; the tall footed bowl holding the candle is an antique Chinese piece, a rough porcelain with celadon glaze. The small bowl is by a Contemporary Japanese potter and the cup in the foreground is one of mine, rice husk ash glaze on stoneware.
    I think the three pieces relate to one another in a similar way, despite the differences in culture and times in which they were made.

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