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  1. I've wondered that same thing about borax, but was intrigued by it because Britt's book showed that Bauer flashing slip was the brightest, and it has borax. I've had the same trouble finding info on borax and on flashing slips in general. Another aspect of borax is that it's soluble. That makes it not a great choice for glazes. However the soluble salts will migrate to the surface of the glaze and you might get some carbon trapping with its interesting surface effects. I don't know if this tidbit helps you, but you're welcome to it.
  2. I think I read in Those Celadon Blues that Jun glazes need to fire a bit higher than cone 10 and that they don't work at cone 8-9. Just food for thought. But I wish you good luck. Jun glazes are amazing.
  3. I grew up in the small town of Riverton, NJ, right across the Delaware river from Philadelphia. A creek that fed into the river had white clay deposits, and I heard tell that a few local people in the 1960s would gather and use it. There were only a few pockets here and there in the 1990s when I started learning ceramics, but when the water washed away the dirt, new pockets would be exposed. Unfortunately, I didn't know enough about testing to do anything with it, but I've always wondered if it was a kind of kaolin ball clay. I know that defies logic, but ball clay is basically secondary clay, and kaolin comes from feldspar that has broken down. Today, I live along the kaolin belt in Georgia, and there's lots of exposed kaolin that gets water washed. This NJ clay was fairly plastic. I once found an article about porcelain clay from northern NJ, but it didn't explain much. I saw this article about the porcelain when it came out and immediately wondered if this porcelain was the same type that I found. Next time I go back, I'm going to look, and if I find any, I'm going to test the living daylights out of it!
  4. Run a triaxial with your granite, any local clay, any local wood ash. That likely will keep you in ideas for a long while. One of my glazes is 33.33% granite, 33.33% local red clay from up the river from my house, and 33.33% mixed hardwood ash from my woodstove. Another is 25% granite, 25% (milled) sand from the riverbank on my property, 25% mixed hardwood ash, and 25% of local clay. This is the 1/3, 1/3, 1/3 glaze: With local materials... it is all about testing. best, ...............john So many tests I've done. I was hoping for a leg up.
  5. If any of you have some successful recipes that you have used with granite, I'd love to know them. I'm working with a group of wood firers who are trying to reproduce local clays and glazes used by Cyrus Cobburn, a Georgia folk potter who was in Junction City, GA from 1830-1840. I have access to local granite dust, a gneiss- hornblende potassium feldspar. I also have access to Georgia kaolin, 200 mesh silica sand, lime stone, Lizella clay and a blue creek clay that is a ball clay. Here is a picture of a granite-based celadon from our last firing. The recipe is 7% oakwood ash, 25% Georgia kaolin, 29% silica, 17% whiting and 22% granite dust.
  6. Thank you. This has been a great discussion for me. I have a notebook where I keep glaze wisdom. I wrote down three things from it that I've never read before.
  7. How do you measure grams per square inch?
  8. I am not an expert at glaze chemistry, but as it happens I have an Olympic kiln and am also dealing with a pinholing issue. I did a ton of reading on it, and learned a few things. So here goes: Boron glazes blister when overfired, so Digitalfire.com says you should trying firing slowly in the last 200 degrees before reaching maximum temp. You can then reduce the soak because you will build up heat work. Tony Hanson's article on boron helped a lot. Does your glaze have a high amount of boron? If so, try reducing the boron. My faulty glaze is high in boron, so I'm mixing about 5 100gram batches and reducing the boron by 2% in each one. Also, is the glaze high calcium or talc? These ingredients have high surface tension, which can cause pinholing. I believe a slow cooling helps with this. Below is the ramp I'm working with to try to reduce pinholes. I'm not going to cone 6 but may go back to a higher temp; I just replaced a new thermocouple that was only a month old. It went haywire. Good luck. Glaze faults are really frustrating. Janice in Warner Robins, GA P.S. Call Olympic about how to program the V6CF. Their support people are very good. #/ Ramp per hour/To Temp /Hold (optional) 1 100 200 2 150 500 3 400 2124 4 100 2160 5 100 2124 15 6 999 1800 7 50 1400
  9. Helios is beautiful in a cone 10 reduction firing. But if you like throwing fancy shapes, it might not work well on the wheel. I found it to be highly thixatropic (sorry for spelling). The more the molecules move, the more liquidy it gets. I like manipulating my clay, so I flopped a lot of pieces and stopped using Helios. But if you throw basic shapes that rely on surface decoration, then bob's your uncle.
  10. I like the red and white stripes in the first pot. In addition to the other suggestions, I would add that rims are under more stress than any other part of a pot because they get handled, bumped, and cracked in the making of the pot, then in use after it is made. If you make your rims thicker, they will be stronger and subject to less stress.
  11. In November 2014, I got to participate in Roger Jamison's anagama kiln firing in Juliette, GA. I was so impressed by his and Jim Sandefur's pots, I decided that I needed to up my skill level.
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