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yedrow

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Everything posted by yedrow

  1. To me, outside of industrial use, ceramic refers to a clay (Al2O3 2SiO2 2H2O) where all of the water has been removed (Al2O3 2SiO2), as John said, an alumino-silicate. Stoneware refers to a clay-glaze relationship, in a manner of speaking. When we say "stoneware" we are talking as much about the glaze as we are about the clay. I'm not sure that stoneware can be very well defined as a clay(body) by itself based on a unified set of qualities. Porcelain, again, in a manner of speaking, is a pure clay that developed from work in stoneware. I suspect the Chinese developed porcelain more out of a search for whiteness than anything. It just so happens that to get white you also get refractory. Porcelain is more like glass (vitreous) than the other clays. Naturally definitions develop from general assumptions into specific observations and then from specific into general categories so some definitions come before the 'specific' part, and some after, leaving opportunities for confusion. Joel.
  2. I was wondering that the zinc might be fluxing something when I first saw it, but I to quickly assumed the structures coming out of the trays were testing probes or something put in after the firing. Now, my guess would be that you are growing crystals. I would guess that the narrow tops are from the lower energy level of the early vapor condensation and accretion on I guess a crystal imperfection, then when the material became more energetic the diameter expanded to allow the molecules to order themselves accordingly. The structure has to be light enough to be lifted by the surface tension of the source material. But, that is a very uneducated guess. Beyond that, wow, how cool! Joel.
  3. Exactly what I've been needing to see, some visual references on flocculation and deflocculation. Thank you so very much! Joel.
  4. You can stop up the refill opening and wax a circle over and around the holes, and wax them closed. That is the best solution I've found. It leaves a patch of bare clay, but that isn't the end of the world. In my experience a glaze quite often does't come off of bisque as powder, it comes off as flakes. So, when you try to open a hole up one or two may drill out clean, but you will always get some that chip out and leave a poorly glazed, uneven area. When doing the drilling method I've always used a small clay knife (blade about 1" long and 3/16th wide, tapering to a point). I twist it as I push it into the hole. This allows me to softly scrape away the glaze and the knife always fits the hole up to the clay. I use the same knife to make the holes and then wallow them out a little to compensate for shrinkage. I've never tried the tooth pic thing, but I've heard of it. I quit making salt and pepper shakers since they're more difficult than mugs and don't sell as well. Joel.
  5. Thank's John! I reread your original post and understand it better now. Joel.
  6. Them are lil' doodads. They're for fillin' in the empty spaces between big doodads.
  7. Is that true for all glazes using lithium carb.? I know lithium tends to go into solution in the glaze [er, slurry], is that also true for the melt? I've just assumed it increased pinholing/blistering. Joel.
  8. I use both a hair dryer and a torch at work. The hair dryer is mounted on a microphone stand and can be adjusted. I use it for larger pieces and I use the torch for smaller pieces and when my lids don't quite fit (who said that!). I'll use the hair dryer when I can do some other work (like waxing) and shift it as needed to cover the piece. I tend to prefer the torch, thanks John! now I know why! Joel.
  9. Cool! Thanks folks, I'm gonna do a glaze test tomorrow or tuesday. I'll let you know how it goes. I'm not sure how soon I'll have any alberta slip and it'll be a couple of days before I can calcine some zinc, so those will have to wait till next week or so. I'm trying to get some ware together to see how well people like it outside of the context of my job. Hopefully one of these will put some blue into my display. Joel.
  10. Perhaps people are suggesting water because when you move heated air there quite often a chance that a spark from any given source might blow into the tank area and cause an explosion. Also, you don't have to actually have the water exposed. You could dedicate some garden hoses and attach them to a sock that you set the tank in. Then you just have to circulate warmed water around the tanks and empty them when you're done. You could perhaps do this from and into a container that contacts the kiln to capture the waste heat. Note, you should always take precautions to not trap explosive gases, keep the tanks well ventilated. Joel.
  11. Atanzey, I'm using Laguna's Gerstely. I can get a real nice blue by putting a matte white from Chappel's book over the FB, but it isn't glassy. Oldlady, I'm afraid I don't have Van Guilder's book. Joel.
  12. Anyone have a reliable cone 6 oxy glassy rutile blue glaze recipe they would mind sharing? I've been trying to get the Floating Blue recipe from here on Ceramic's Arts to work but it always comes out as a semi-matte (grey to greenish). Joel.
  13. I would first check to make sure there isn't something wrong with the bat. Joel.
  14. I love butterscotch over Daly red. It comes out mottled golden, almost like it's glowing. Joel.
  15. I don't know enough about this to really comment, but,I think that LPG is made up of propane and butane. Propane boils off at something like -40 deg. F. and butane boils at around freezing. If you use small tanks in sub-zero temps you will use up the propane, but not the butane. If you don't completely empty the liquid you will end up with only butane in them and it won't produce the gas you need or the pressure to push it out of the tank. Just brain storming, but I'd try to use the heat of the kiln to warm the tanks. Perhaps run some copper tubing around the stack and circulate water into a tub with your tanks in it. If you could get a variable speed pump you could then find a rate of transfer that didn't outpace the tanks and risk overwhelming the pressure relief valves. And, the heating would be regulated by the process. Joel.
  16. Fluxing slips have a place since they will lay down on horizontal surfaces (pie plates) and move a bit on vertical surfaces. I've been wondering about putting some 3134 in some slip to get this effect but I've been concerned about shrinkage as Marcia mentioned. I've also been thinking about trying some whiting or Gerstely borate. I just need to do a test. I've only recently started working with slips and it seems to me that the possibilities are endless. Leoj
  17. I like lifting the pot most because it feels like I'm on the up side of a swing (playground style, with long arcs). Joel.
  18. I think of the walls, bottoms, attachments, etc. of pots as being themselves vessels which will hold a certain amount of water. If you bisque hotter, they will hold less water. And, of course, if you wet them they will hold less water too. If your glazes are tuned to dry bisque then you will get a different look. I personally don't like doing it since it is hard to control the variables in the bisque to glaze process as it is, introducing another difficult to control variable just seems undesirable. Joel.
  19. Thanks Marcia and TJR. I think I've written these solutions in some form down three times already, perhaps at some point I'll be able to find one quickly. Joel.
  20. I guess I don't trim and stick handles when I should. I let the clay get too dry then end up dipping it in water to rehydrate it. For some reason it seems there should be negative consequences to this, but unless it's changing color I seem to get away with it. Joel.
  21. I've been having trouble with a couple of glazes and for months have been wondering if it was a flocculation issue. At this point I'm thinking that my water is probably the issue. But, during this time I've been trying to get my head around flocculation and deflocculation and have been trying to find a way to actually physically see a cause become an effect. This week I was reading about slips and it occurred to me that I've been going about this all wrong. I should have started with slips from the beginning. Slips are mostly clay and when trying to affect the flocculation of a glaze one is mostly working with the clay in the glaze (usually a fairly small percentage of total volume). So if you focus on slip you can presumably see the effect more clearly. So far I've deflocculated a slip after the fact with sodium carbonate. I learned that it is probably best to deflocculate the water you will use to make the slip then to mix the slip with that water, thus keeping the water content down. I also need to use an equal amount of sodium silicate with the sodium carbonate and see if I can generate an observable reaction. One of my problems with test amounts has been the skewing of results by mixing in amounts of water (bearing the flocculant/deflocculant) that change the rheology of the mix. Thus, the idea that the flocculant/water solution should be mixed first then added. I'm guessing this should also help in managing the amounts of flocculant/deflocculant with reasonable accuracy. This is pretty exciting to me and I hope someone out there is helped by my experience. I'll post more as I go. Joel.
  22. Alice, I don't know that there is one. I'll look though. It is another guy's scale and I'm not that familiar with it. Now that you mention it I think I'll turn it over and see if there is a shut off for the time out feature. Thanks! Joel.
  23. I had an aggravating day with a digital scale at work today so I thought it appropriate to note that when you buy a digital scale you might want to find one that doesn't click off when you are in between materials during a test, augggggg. I would put a chemical in the beaker then get another chemical and while my back was turned the evil thing would time out and turn off. Pure evil I tell you! Joel.
  24. Ack!!! Glad you mentioned that. I got Insight this week, in part because it was on sale. My knowledge of what a glaze is, is growing rapidly from having done so. Digitalfire also has video tutorials and a great data base. With the tutorials I'm moving along at a nice pace (or at least feel that I am). Also, Tony has been great to work with. Joel.
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