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About glazenerd

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    Clay chemist

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  • Location
    St. Louis, Mo.
  • Interests
    Crystalline glaze chemistry. Been stuck in clay chemistry and formulation. Writing formula limits for porcelain, stoneware, and low fire bodies. Developed new cone 04 colored porcelain body, cone 6 porcelain, and cone 10 bodies for public use.. 60yrs old.

    Email: optix52@aol.com

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  1. John: easy enough to test- couple of drops of vinegar that foams up- salts.
  2. Okay, so now I am curious? Does your throwing water or pieces shown have the classic mold smell? High organic content ball clay would produce this kind of mold, but the body is usually much darker. This does remind me of soluble salt migration as well.
  3. Titanium, calcium, iron clay body

    Blending various blends of raw clay to set levels of titanium, iron, and calcium. The goal was to produce purple in oxidation: without the use of stains. A band of rutile was placed in the center, and Temmoku glazed over.

    © TJA 2017

  4. The issue with Laguna Iron Phoenix glaze...

    Glaze chemistry begins to matter when your glaze starts peeling off your pot. What you breath in does matter: in 1978, I worked on a rehab job in South St. Louis city. Every day, we would use a compressor to blow off all the dust that accumulated on us from working. After a month, a city inspector shut down the job once they figured out that dust was asbestos . All the overhead pipes had 4" pure asbestos pipe insulation. Back in the days before asbestos became a big concern, and masks were an after thought.
  5. The issue with Laguna Iron Phoenix glaze...

    I recall getting an email forwarded from Laguna, by my supplier. They were looking for crystalline glazers to test several new zinc varieties. Their existing supplier ( Horsehead Cerox 506) had discontinued production, and they were testing four new zinc products. One from China, and three from Zinc Nationale (Mexico) as I recall? They had been using a white French process zinc that was giving them some issues. White zinc is French process that will begin vaporizing at 2260F +/- (tested). Yellow zinc is sphalerite (American process), which can fire up cone 11 without issue.(tested) You may very well have gotten a batch during this period of transition? The ingredients in the MSD sheet only add up to 70% or so, which means 30% of something is not listed. Most likely Nep Sy, which has 14-20% soluble salts pending mineral source. Sodium will certainly form crystals as it sits, which if discarded during sieving would alter the flux level in the glaze. If enough sodium, along with lithium crystals were sieved out: it would effect the melt and clay/ glaze interface.
  6. Remnants from the Garden3.jpg

    Really like the detailing on this piece.
  7. microwave proof?

    Relative to this topic: a niche where clay becomes as important as glaze or firing. Oven ware, flame ware, or by application: microwave "proof." Every time you heat a pot, rather by heat or microwave, you are dealing with expansion and contraction. It is one thing for a coffee mug to get a quick shock of heat, and another for a piece to be subjected to increasing amounts of heat over an extended period of time. what Chilly and Joseph added is relative: but in this case so is the clay. Ovenware, flame ware clay bodies are low expansion: 4.25 up to 4.75 median average. The lower expansion of the clay, the more resistant to shock it becomes. Wall thickness also comes into play: the more clay present equals more clay that expands. The lower COE clay also means extensive adjustments in COE in the glaze of choice to fit it. Spodumene will quickly become your friend, should you venture down this road. I will let others work the glaze side of this equation, being a clay guy primarily. nerd
  8. "Get the excess clay out before you raise..." expound please.. Apparently I am missing this info.
  9. Ian Currie Test Tiles Forums?

    Joseph: those who interested will respond, those who are not -won't. We "rabbit holers" like being down here. Every once in awhile the queen of hearts speaks.
  10. Okay Prez- now for a question. the biggest problem I am having is leaving too much clay in the base. I never seem to be able to pull all the clay up the cylinder. My wall thickness is getting very close, but I would "guess-a-mate" that I am leaving a third of my clay in the base.
  11. My bullet blender, I mix glazes as I use them. I dry sieve and then mix.
  12. NCECA

    Ron: think I better give you a heads up before you go. 1. When talking with potters at NCECA; when their eyes start glazing over when talking pottery: move away slowly. You are about to hear either very detailed explanation of their last firing or favorite glaze recipe. 2. Potters with white name tags only mean they have been cooking clay for over 30 years. 3. Leave your bill fold and credit cards at home: you could easily spend more than you make. 4. The old pottery guys who have been firing for decades all have beards...right Fred? 5. Those with no sense of humor should not read this post.
  13. Ian Currie Test Tiles Forums?

    Pieter: i have noticed when firing crystalline glazes that high percentages of cobalt would make the glaze boil. Although, the 25% zinc addition has to be considered as well. However, high copper additions always retained a smooth finish. Relative??? Just an observation. I have played with SiC in cone six red recipes. It seems to favor calcium and potash in a melt. i have had better success with SiC when I chemically reduce it beforehand: which I will not discuss here. Mr. baymore made a very logical point in another thread recently about the forum audience.
  14. NCECA

    Ron: i enjoyed attending NCECA in KC back in 2016. Lots to look at and take in. I did notice a mass gathering at the bar in the evening, with lots of pottery talk. I went specifically to meet with Ron Roy, but also had the pleasure of talking with Marcia Selsor and a few others. Spent several hours talking with an old wood firer from Maine: who was every bit as obsessed with wood firing as I am with clay. I had to bug out early because of business meetings; but wish I could have gotten in another day. If you can go, do it!!!!