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Min

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Everything posted by Min

  1. Look for the kiln manual, you should be able to find it online if you search by it's name. Also, do a search for the name of the kiln controller if it isn't included with the kiln manual info. If you don't have any luck then post a picture of the controller and kiln here, include as much info about it as you can. With kiln controllers there are usually options for doing a fast or slow firing, some controllers have the option of fast, med, slow and also different preprogrammed schedules for bisque or glaze (among other options). A soak (or hold) is entered manually, you program the schedul
  2. By seasoning the elements what you are doing is allowing the elements to build up a protective layer of (mostly) alumina oxide. When firing clay and glazes the alumina oxide coating on the elements prevents the corrosive gases that occur during firing to prematurely age the elements. Keeping the plugs out and propping the lid slightly allows more oxygen to circulate through the kiln which helps in forming the alumina oxide layer, or if your kiln has a vent then run that for the entire firing. If you only ever fire to less than 1920F or if the kiln is made of fibre then preconditioning isn't n
  3. That first recipe, Soldate 60 doesn't look like it would be nearly as tight as the Laguna Soldate 60. Don't know what other clay suppliers list the absorption at for their versions of it but I know Laguna's is less than 2% at ^10. May I ask where is that recipe from? What are you looking for as far as claybody colour? Also, does it need to be low porosity at cone 6 or just mature at 6? Welcome to the forum.
  4. Leach's 4321 has been around for ages with spar not nepheline syenite, I don't think that's an issue. @jdedini did you measure the specific gravity of the glaze before using it? I'm wondering if you just have it with too high a specific gravity. You mentioned the glaze was fairly thick, with only 10 clay it shouldn't look fairly thick. However the iron in the one version of it can cause the glaze to appear thicker than it actually is, iron tends to gel a glaze somewhat, after sitting for a few weeks this tendency diminishes as some of the solubles in the glaze help to deflocculate it.
  5. It's a good idea to test your claybody before you make a lot of pots with it, especially if you are making functional work like mugs and bowls. I would strongly suggest testing both the wide firing clay if you are using at cone 6/7 and the wild clay / commercial clay mix. The broad range commercial clay you could probably just test for absorption but the wild mix I would run a slumping test and an absorption test on once you get the tests narrowed down. If you need it there is a good article here that includes how to do these tests.
  6. Go by what your clay is mature at, if it can take a ^5 plus X amount of time in a soak and the glazes look okay then you're set. Since you are making functional ware test the claybody at the cone you fire to, be it 5 or 6 or somewhere in between. Glazes melt along a range, there is a spectrum of both time and temperature upon which they both melt on the way up and solidify on the way down. The reason the drop and soak works on a matured claybody is that some glazes have a surface tension that is too great to allow glaze bubbles / pinholes / craters to heal over; lowering the temperature b
  7. You can get to cone 6 by firing to 5 and doing a soak, but if it's to reduce pinholes I'ld suggest trying going hotter than ^5 then doing a soak then dropping 100F and doing another soak. With my kiln what gets me a perfect cone 6 is going to 2180F then holding for 15 minutes then dropping at 9999 to 2080F and holding for another 15 minutes. There are a lot of reasons for pinholes but if it's from the glaze not smoothing out this schedule works really well. If you can monitor the cone(s) at the end of the first soak you are looking for the cone 6 to be where you want it, the second soak doesn'
  8. If you have a Dremel tool that could work too.
  9. You could do a line blend with a cone 10 claybody and your local clay, fire the test pieces in little shallow bowls to catch the ones that run. If you can get a dry mix cone 10 stoneware that would be the most accurate to measure out weights and combine the two evenly but even using wet clay will get you in the ballpark. I'ld start with 95:5 (cone 10 to local) then go by 5% increments until you get to 65:35. If you don't want to purchase a cone 10 stoneware its fairly simple to mix up a dry batch of cone 10 stoneware clay.
  10. When a name is tagged like this @Not so famous it means the person writing the post is referring to them or something they wrote. In my post I tagged PeterH, so my comments were in reference to his post. Peter gave a link to a potter who uses a recipe containing no manganese. He didn't do a direct link that you can click on to go to the page but could cut and paste it. No manganese in the recipe Peter linked to, it's here. (click on the green "here" to access it without doing a cut and paste)
  11. If you are sure that in no time in the future you will want to fire higher than earthenware/lowfire then the cone 6 kiln would be fine. If the tags etc don't need to be non-porous then earthenware should be fine. It will save you a lot of electricity costs not firing to cone 6 and also the elements won't have to be changed nearly so frequently. But, you won't be able to fire midrange in a cone 6 kiln very often without rapidly wearing the elements out.
  12. I have issues with the mining of lead and the making of the lead bisilicate, frits etc. It’s inexpensive and makes lovely looking glazes but I don’t think the cost to those involved with the processing of it is justified in this day and age. It’s also available to hobby potters in parts of the world, including here in North America. (US Pigments sells it)
  13. It doesn't have to be that glaze specifically, but what you will need for those effects is a fluid glaze. If you use a stiff non moving glaze it isn't going to pull the cobalt from the black underglaze and cause the streaking. Make up some test tiles and try whichever commercial glazes you have, applying them a bit on the thick side will help it to run a bit too. (just not too thick or they will crawl)
  14. I would argue that it's not wise to use lead bisilicate at any temperature. Frank Hamer states lead bisilicate as partially volatilizing above 1200C / 2192F. Before it gets to that point it's going to cause issues with the glaze as it passes out of it, I would imagine bubbling/craters would be an issue.
  15. It could just be that they are trimmed too thinly where they are cracking, micro crack from uneven drying that opens up during firing.
  16. Break some open and look at the cross section. Are they thrown as one piece and trimmed or are you joining pieces? Frustrating....understandable but it comes with the territory. It’s solveable.
  17. 1300C is cone 10 so a kiln with this rating would be fine for any clay that fires to that but elements will last longer when not fired to maximum temperature. Stoneware can be midrange (approx cone 6) or highfire (approx cone 10). There are also midrange and highfire porcelain bodies. Any clay is at its strongest when fired to maturity. Cone 6 and 10 clays are going to be more durable than lowfire clays, cone 6 is going to be easier on the kiln and cost less to fire (electrify) than 10. If you go with cone 6 then use a clay that has that as the top firing temperature, not a wide firing range
  18. I believe he uses Campana's Clear Base and fires to cone 6. In the video he is using underglaze (and sometimes wax resist) on greenware which is then bisqued and glazed. I'ld send him an email and double check that this is the glaze he is using. Campana’s Clear Base cone 5-7 11 Spodumene 21 Frit 3134 20 EPK 20 Silica 20 Wollastonite 8 Zinc Oxide Welcome to the forum!
  19. I don't think that's going to happen. His NCECA presentation "What makes a teabowl a Chawan" is available though.
  20. We all know that chawan are steeped (no pun intended) in history and culture. When we choose to make those or any other culturally specific item I think we need to consider if we are practicing cultural exchange, assimilation or appropriation. We need only look at history to see the differences between the three. I get what Mark is saying, it is an example of an even exchange between equals, one isn't trying to subjugate the other and it is done with respect. No, a sponge holder (even one of Marks) doesn't have the history behind it that chawan have but it demonstrates the respect aspect
  21. You can get alerts from Craigslist so if something comes up you'll get either an email or SMS. How to here on signing up for them. There are also the Facebook groups "Potters Used Tools and Equipment" and "Potter's Attic Again". If you have a local pottery supply place you could see if they have a bulletin board with wanted and for sale equipment also. Even just going in and talking to them could be helpful, they might know of someone who recently bought a new kiln and have a used one for sale. There is also the Community Marketplace on this forum.
  22. Started out as a recipe that was altered by Martin Butt. He had Laguna make it for him then when they started selling it to other potters the "Butts Mix" got abbreviated to B-Mix.
  23. Yup, same liner glaze in both pots, porcelain on the left, b-mix on the right.
  24. Probably not. I agree with Sorce, I think most people would bring them in at the end of the season. At <1% absorption they should be fine. I looked up this claybody, just to confirm it's this one right? Under the description it says it "fully vitrifies at cone 5, but will fire at cone 10 beautifully". And under the specs it has absorption at 1% +/- 1% but it doesn't say this is the figure for cone 5. I don't think it is, I think that is the absorption figure for cone 10. Before making a lot of plant markers with this claybody I'ld do your own weight absorption tests. (link here on
  25. Hi @muddkat and welcome to the forum. Not a silly question at all, just one that probably needs testing to find an answer to. As always, try it and see what happens. If you are just starting out with glazing I would really suggest making up a lot of test tiles so you can try your experiments with those rather than your real pieces.
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