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glazenerd

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glazenerd last won the day on July 30

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About glazenerd

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    Clay chemist

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    Male
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    St. Louis, Mo.
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    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. Finally put twelve pounds on the wheel, my first time over 5-6 lbs. my final conclusion was: I would rather make clay than throw it. Turned out - so so. 

  2. Stoneware Limit Study

    Unfortunately, I have not been able to edit my picture size-yet. Edit button does not come up when I double tap pic. This piece is just slightly larger than a shot glass: 1/8lb. of clay perhaps. Spent perhaps 30 seconds forming it and then into the hot sun it went. All I know at this point is: WOPL = 29. Nearly zero plasticity. All material passed through 100 mesh screen, and less than half through a 200 mesh. From that: alumina 30%, silica 45%, iron 12%, potash 5-6%, titanium 3%. All guesses of course, but comparing the WOPL, color, and mesh sizes to my extensive clay database: close. Will do more formal testing once I figure out if it produces the color and effects I want. Threw away a couple thousand test bars few months back, so pardon my refusal to make more at this point. Nerd Edit: I am wondering if this is a chlorite group/ clay. 2:1:1 with double tetrahydra inner layers: iron fe2 / fe3. This is close enough to the Arkansas border, where chamosite deposits are common. If that holds true, then iron levels can be over 20%.
  3. Mixed up a porcelain and stoneware body with the high iron clay from the old brick yard. Already fired 100 gram samples, now for the 1000 gram samples. For some odd reason I sprinkled some 50 mesh grog in: get out of my head John. 

    1. Joseph F

      Joseph F

      Nice. I am about to fire some clay myself. Fun Times!

    2. LeeU

      LeeU

      Very funny (grog/John).  Tempting to run out and buy some Grogzilla and mix it into Southern Ice. 

  4. Stoneware Limit Study

    Cone 6 firing to 2232F, no hold produced this: 50% raw clay, 25% silica! and 25% potash spar. One area has a coat of temmuko, then a raw area that self glazed, then a coat of white on the back that looks nasty. So there has to be a fair amount of spar in the clay: it self-glazed in the raw areas. Now I tend to think there is more than 12% iron! with a fair amount of titanium. At this point I am content enough to have a raw sample analyzed. nerd
  5. Na5AlO4. sodium aluminate Nep Sy precipitates 14-20% soluble sodium salts. Notice the complaints about black specks have increased over the last five years as Nep Sy has become the flux of choice. Normally soluble salts would form white crystalline nodules or powders in clay or glazes as they dry. However, every time sodium (Nep Sy) comes in contact with moisture, hydrolysis occurs: IE- hydroxols. So sodium hydroxide is coming in direct contact with aluminum ( wheel head) so instead of precipitating as white powder, it is picking up alumina to form sodiumaluminate that produces black/silver specks. my best shot..Nerd
  6. Brandee: TY for reporting back, always good to hear about the final remedies.
  7. Stoneware Limit Study

    I have been making trips to old brick mines across Missouri on and off all spring. This past week, I visited one that had been closed for over a decade. They made dark brown and nearly black bodied bricks: the reason it got my attention. I collected nearly 600 lbs. directly from the adjacent clay pit. Going to fire this 100 gram test cylinder tomorrow. I suspect the iron level is above 10%, because I can see signs of oxidation on the sample already. One level cup weighed over 400 grams, as a comparison OM4 weighs 253 grams per cup. This is a ball clay by the way, it is not fire clay. nerd
  8. Neil: the body is rather obvious in application. 10% would be tooth, 30% would be dentures. Clore: you are approaching it in the right way: comparing chemistry to the closest chemistry. Perhaps ask your local supplier if they have a product anywhere related to a finer mesh grog. Molochite is sold 120-200-325 mesh. The recipe does not state which mesh, although in the States 200 is the most widely available. Nerd
  9. I am struggling trying to understand why molochite is even in this low fire recipe. Molochite is a calcined, high temp grolleg. (Cone10-12) Nerd
  10. Indie and go fund me efforts

    As with any public venue created with good intent, it is quickly over-run by those with wrong motives. There is no screening process, so it's donor beware. To Mea's point: there are disciplines and lessons that can only be learned by going through the fire. Being a fiercely independent soul: I make and pay for my own way, and with that comes the expectation of having no expectations or desire for others to help. Then when others do offer to help, it then becomes a blessing of kindness: even though I decline. Nerd
  11. Glaze aftertaste

    Julie: then borrow some porcelain from a potter friend and make a few small cups . Glaze using those mentioned: if there is no after taste- you are down to a clay issue. strange question perhaps, but it has a purpose. Does the water you use to throw develop a pungent smell in a short period? The darker the clay body: the higher the sulfate/ carbon content. Organics in a clay body develop a musty/rancid smell in the throwing water in a short period. If you change water everyday then you probably have not noticed it. If you let it sit a few days, you will. Nerd
  12. Joseph: that is one of the traditional remedies: but not what I had in mind.
  13. Glaze aftertaste

    John: I would like to add a caveat to this topic and to the "weep" test. Stoneware clay bodies hold moisture on their inner platelettes, whereas porcelain only hold moisture on it.s surface. An example: OM4 ball clay will hold 35 grams of water in every 100 grams of clay material: without showing any signs of weeping. That number is much lower after a firing: if immature it would be in the 3-5 grams of water per very 100 grams of material. Simple math: an 1lb. Mug could conceivably hold as much as 12-20 grams of water without showing any signs of weeping. Compound this by the exterior glaze being vitrified, and trapped water unable to pass through it. So while the weep test is one method of testing, it is not a definitive test for a piece holding/releasing moisture in the clay. If a scale is accurate enough: fill the piece with water and let it sit 24 hours and empty the water and towel dry. If the weight before and the weight after differs: it is holding water internally. Immature stoneware would be highly susceptible to this problem. i would recommend making a 4x4 tile using this (or any) clay and fire it to maturity unglazed. Let it sit in water 24 hours and towel dry before weighing. If the weight differs before and after the soak period: then you know with certainly the clay is holding water. This differs from the standard boiling test: but it will give a quick insight into the problem. Hate to be offensive, but I suspect the after taste is from fungus growing inside the clay walls. Nerd
  14. Joseph: as soon as I finish working on a drying spritz: will deal with the GB issue. My last test with the spritz: the test piece dried within 90% even-ness from top to bottom. Going to test a few bowl, platters, and other shapes before I realize that info. I do not think the GB properties will be too tough to solve. Nerd **edit** testing to date has been without using plastic covering.
  15. V-gum is a binder for glazes: that like any gum keeps them in suspension. In this case however, because V-gum also has a tacky quality, they are using it to help bind glaze to the piece, and as a brushing medium. I started to once fire some time back in order to save time, save element life, and to save money. I developed my own nerd suspender that does what V-gum does for 1/2 the price. My schedule is: 160f to 1150F ( gets you past quartz inversion at 1063F) 250F to 2050 F 125F to 2230F ( no hold in smaller kilns) i do not have pin-hole issues, good uniform melt, and vitrified. Not a fan of 2190F with long hold, although it is common practice in pottery.
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