Jump to content


  • Content Count

  • Joined

  • Last visited

Everything posted by Min

  1. 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
  2. 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!
  3. I don't think that's going to happen. His NCECA presentation "What makes a teabowl a Chawan" is available though.
  4. 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
  5. 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.
  6. 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.
  7. Yup, same liner glaze in both pots, porcelain on the left, b-mix on the right.
  8. 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
  9. 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.
  10. It's also common to throw large pieces thicker with porcelain than you would a like sized piece using stoneware then trim away a lot of the excess porcelain. I have friends who have spent time in Jingdezhen China, they do speak of the massive pots being thrown in sections and trimmed down. They have also said that studio potters are very rare; it's standard practice to do only one part of the process there. If you throw you only throw, you don't do brushwork decoration, you don't glaze and you probably don't fire your own kiln. You specialize in one part of the process then the pot moves on to
  11. From Euclids (major kiln element supplier): "Pre-oxidizing the elements is recommended for customers using their kilns at elevated temperatures (cone 6 and higher), or under corrosive or reducing conditions. To oxidize the elements, heat your empty kiln to a temperature above 1922F/1050C with the peep holes open and the lid raised slightly. Holding the temperature there for 6-8 hours will ensure thorough oxidation of the elements, but most of the oxide growth occurs in the first 1-2 hours. This procedure grows a protective oxide coating on the elements before the elements are expos
  12. 0.78 isn't an absorption figure its the target ratio for clays being less than that for closed vs open porosity. Brick industry uses a figure of less than 5% regardless of open or closed porosity. Example would be if you have a claybody that has a closed porosity of 2.5% and an open porosity of 2.75% then the math would be 2.5 divided by 2.75= 0.91 (rounded) so going by the ratio alone this would fail as an outdoor body as it is above 0.78 but since both closed and open porosity fall well below the 5% (open or closed) figure it would pass. Need to measure both open and closed
  13. It's not going to make any difference if the stain alone is fired onto the pot prior to glazing, stains have been fired in their processing so refiring to bisque temps isn't going to change anything. Another reason it's good to add kaolin to the frit plus stain mix is the clay (kaolin) helps prevent the frit plus stain from dusting off the pot, especially when being handled. BTW I've noticed that in England there are also "underglaze colour stains" available in addition to stains alone. If you by chance have some underglaze stains then all you need to add to them is a brushing medium.
  14. @Sorcery, have you done the open vs closed porosity test? Clay needs to be less than 0.78 (in products firing to more than 5% porosity) in order to pass CSA and ASTM specifications for outdoor use. A little anecdotal evidence that high porosity clay can survive freeze/thaw conditions if it has an open pore structure. I made several really large outdoor planters about 30 years ago, all of them are outdoors and unprotected year round. I made them with Fairey 78G clay and single fired them to cone 6. This is a really groggy cone 10 clay, at cone 8 it has a 10-12% absorption so even though I didn'
  15. Start with the easiest things first, what rate are you trying to heat the kiln at when it gets the Failed to Heat error at? Usually this error comes up when the elements are getting old and they can't put out enough heat to keep up with the program. Then move on to the more in depth investigation. At this point I'ld stop the firing, unload the kiln and turn the power off. Second, open up the box up (no power) and visually check the wires and connectors, particularly where they enter the kiln (look for discolouration or burnt wires) Third, check the resistance and continuit
  16. Chromium oxide is very refractory, if you use it for brushwork under a glaze chances are the glaze will crawl away from it. If you do use an underglaze containing chrome make sure the covering glaze is zinc free or you will get brown from the chrome + zinc. Big difference between what potters use, chromium oxide, versus the hexavalent form of chrome in regards to toxicity.
  17. I played around with what you have available and came up with a possible sub using your ingredients for 3134. It's not exact, main differences are: there is magnesium in it whereas the 3134 doesn't contain that, sodium and calcium is a titch lower but with the magnesium this should offset the lower flux amounts of those. LOI goes from 0 for the 3134 to 15.2 (but this is still about 1/2 of what it would be to just use gerstley alone) Boron, alumina and silica are equal. You could mix up 100 grams of this blend and try it 1:1 for 3134 in a test recipe and see how it comes out. Mag
  18. @Babs is it for just one recipe that you need a substitute or in general? From Glazy, 4108 as the first chart below and 3134 as the second. Do you use 4108 as a sub for 3134? Wasn't sure if I was reading this as you use 4108 as a sub for Ferro 3134. Ferro 3134
  19. It's crazy busy here too. I think part of it also people don't know what or when the next restriction is going to come along. I've had people buying Christmas gifts since the end of summer just in case we go into another "essential stores only open" lockdown again. What's taking so much time now is the back and forth emails with customers about their orders, I spent most of yesterday answering emails and bagging up pots, one sweet lady took 21 back and forth emails before she made up her mind. It is what it is as they say. @GEP, whats a Breakfast Bowl? A cereal bowl?
  20. I can't imagine how awkward it would be to center clay with the wheelhead above me like in the image Peter posted, I get that gravity would help in pulling the pot but centering? Think it would be really hard on the wrists centering upside down like that. It gets to be second nature using your hand, redi-rod attached at the side of my foot pedal with a knob on the top.
  21. Spectrum 570 Hot Pink uses a cadmium inclusion stain, it remained true to colour at cone 6 when I used it. It did flux enough at cone 04 bisque to form a sheen but is fine at a 06 bisque. I believe Speedball pink uses cadmium inclusion stain also, plus it's a fair bit less expensive than Spectrum.
  22. The late John Glick wrote an article for Studio Potter a number of years ago which changed the way I position myself at the wheel. In his article Glick writes of throwing while standing and having his back braced against a support, I don't find the need to brace my back but my lumbar discs weren't in the shape his were. After around 10 - 15 years now of throwing while standing I can say I don't ever get back pain from throwing. I don't know if hip, knee or ankle issues would exclude this method of throwing for you or any of your students but perhaps it's an option. To Sciatica and Back
  23. Which Spectrum pink underglaze and what glaze did you use?
  24. Put the slip through a 80 or 100 mesh sieve/screen before you try to use it so it doesn't clog up the tip, if you use a 100 mesh screen then I'ld water down the slip first then screen it then leave the water to evaporate out, otherwise you'll be there all day screening it. Get it on the pot as soon as you can handle it, the drier the pot is the greater the chance the slip won't adhere well.
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.