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  2. Thank you for this very detailed explanation, Min. I honestly appreciate it so much. I feel a bit stupid, firing the underglaze to vitrification temperature - I know that glazes don't take well on vitrified clay so I'm not sure why that completely went over my head. With regards to these pendants, they actually look really nice as they are without an overglaze, so for this batch I will leave them as is: 20190923_074045 by Rachel Brown, on Flickr If I wanted to repeat this process to accomodate a transparent overglaze in the future, do you think the following would work: 1. Bisque fire casts to Cone 05 2. Paint on underglaze and fire to cone 015 to burn off impurities 3. Paint on overglaze and fire to cone 7 (will mature at 6) to create final, vitrified piece. I don't think I could do liambesaw's suggestion of painting onto greenware, as the pieces are so fragile before bisque firing - it is very easy for example to chip off an ear on a pendant once dried. With regards to crazing, the supplier has recommended this exact overglaze to pair with the slip I am using from the same supplier. It is designed specifically for porcelain. So hopefully it will be okay, so long as I fire to the correct temperatures.
  3. Today
  4. My Last fire last week both cone 11 and cone 10 went down exactly togther in unison in same cone pack -this has happened many times-both cones show end points in same cone pack .Its not defective cones just normal wierd stuff with temps and reflected heat and downdraft flow.
  5. Bone ash, I didn't even think about that! Every so often, I have students ask, if you could get rid of a body, in the kiln. With a deadpan expression, I say "Yep"... Then walk away.
  6. I don't use cones in my regular electric firings, but I do in wood firings. My higher temp cones (9-12) bend backwards at the tip first then drop forward. Provides a nice early warning.
  7. Potter is dead. No one to ask. Was years ago so no batch clues. What I posted is what I got.
  8. Thank you so much for your replies. I’m in Australia. I didn’t really phrase my question very well. I’m very new to this. I have some pieces made from white earthenware clay and some made from mid-fire porcelain clay. I had them all bisque fired. When I picked them up the eatherware and the porcelain items were all mixed together. I now want to put some under glaze and clear gloss on them and fire them again, but I’m not sure which clear gloss glaze to use. I have purchased one tub of gloss for earthenware and another tub to use on porcelain. Which one should I use? And how should I fire them? Thank you soooo much!
  9. @SweetheartSister, the main reason glazes craze is because they don't fit the claybody. Crazing happens because the coefficient of expansion of the the glaze and clay are too far apart. As the glaze cools if it contracts more than the clay it will be in too much tension and it will craze. The only way to know if the glaze is going to be craze free is to do a test piece or two. Since you have already fired the pieces to maturity you could use a lowfire glaze on them now, test before you do your real pieces, and glaze fire to the recommended glaze temperature/cone. Or you could use ^6 glazes and refire to maturity again. There is a risk of the clay bloating if it gets overfired. As you have already fired these pieces to maturity once the added heatwork involved in firing to top temp again increases the risk of bloating (or warping and slumping). Tiny kilns like yours can fire super fast, I would use the slow speed the first time and see how the glazes turn out on test pieces. The glaze isn't going to want to stick to the now mature clay, brushing glazes contain gums to help them adhere and flow smoothly, if you have the option of using a brushing glaze that would go on easier than a dipping glaze. Are these the same pieces that you were asking about stilting when firing? If you want to apply the underglazes to bisqued clay then you could either glaze them after the underglaze has thoroughly dried on your 05 bisque or rebisque them to a low temperature to burn off the gums etc that they contain. Don't need to go very hot, just to around 820C (approx cone 015).
  10. Have you tried contacting the seller, to see if they can provide any info ? What are the other "supplies" in the lot ? Perhaps there are clues about firing temperature in some of the other materials. If there are glazes- What cone are they labeled for ? Is there other clay that is marked ?
  11. Next time apply the underglaze before you bisque @ leather hard. That way you only have to fire twice. Underglaze is usually applied to greenware and bisqued.
  12. Yesterday
  13. I have a few dozen porcelain pendants in the kiln right now. This is my first time using porcelain and since having a bad experience with crazing on my last pendants (in earthenware) I really don't want to mess it up. This is what I've done so far - 1. Bisque fire to Cone 05 at medium speed. Although I have now discovered that if you don't put a hold on my electric kiln, it will shut off when it reaches each temperature and will not soak the ware at that temperature. So going by my pyrometric cones, they reached cone 06 (orton cone puddled) but did not quite bend my 05 cone. 2. Then I hand painted my pieces with Amaco Velvet underglazes and set the electric kiln to cone 7, firing at medium speed once again. This means it will definitely mature at cone 6. Firing range of the slip I'm using is 1220 - 1300 celcius. Cone 6 is 1220. I've put orton cones in again to be sure that the ware reaches cone 6 and therefore vitrifies. 3. The final stage will be to apply the transparent overglaze. This also has a firing range of 1220 - 1300. Should I fire at Cone 7 again? Should I fire on the fast setting or on the medium again? I have a Paragon Firefly kiln and according to the manual the medium speed is 'standard', the fast speed is 20% faster and the slow is 20% slower. I want to make sure I get these right this time, but feel quite nervous. These porcelain pendants will be used as part of fine jewellery pieces and I want them to last many many years and not craze on the surface. Thanks so much everyone.
  14. Thanks Bill and Liam for the advice. I'm going to experiment with it and will let you know if it is successful
  15. Sure why not, you can skip the first few steps of grit too. I'd be sure to put a healthy amount of filler beads in there too though to help cushion them from bashing each other apart.
  16. This was in a batch of pottery supplies I got off Craigslist. There was no description on the bag. There is a lot of grog in it; more than normal to my experience so the previous potter may have added some. I went ahead and threw it just to use it up but I can't make up my mind what cones to bisque and then fire it to. Anyone want to take a guess at what body this is and it's firing ranges? Other than multiple, different cone firings of samples is there a method of testing?
  17. Working with a coarser clay makes the smooth process a little slower, I got into coiling when I was in college. I took a archeology class that was in a competition with other colleges to replicate Anazai pottery. It was held in the pottery studio and I was the only clay person in the class. The professor taught the class how he thought they made the coiled pots, I told him he was wrong that the pots would crack and fall apart. At the end of the semester we fired them in a trench firing, my work come out fine the rest was broken shards. I had a dozen pieces come out of the firing most of them quite large and thin walled. The professor admitted I was right, the archeology department won the competition with my work. Denice
  18. I think you would have success depend upon the desired look. While we have not used a polisher we have achieved various looks by sanding, polishing and burnishing even to a low gloss. By sanding I am talking 500 to 2000 grit. We found it pretty easy to polish to a mild gloss with some effort. All of our items are fully vitrified porcelain. It definitely is easier to use a glaze that provides the intended look though.
  19. Just a little thought I had today...if I wanted Cone 6 fired porcelain to have a satin/low gloss finish without the use of an overglaze, do you think that I could achieve this using a rock polisher? I'm talking about very small items - pendants and beads. I would be interested to know if anyone on here has ever tried putting porcelain in a rock tumbler machine before?
  20. Hi Min, thank you for that suggestion because I would have never thought of that. If the method I'm trying today doesn't work out then I will certainly give that a go!
  21. @LouiseB,this is a long shot but I noticed you used the word "bin" so I'm guessing you might not be in North America. In the UK for example there are some earthenwares that go to cone 6. What info do you have for the earthenware you are using? Might be lucky and have one that goes higher than lowfire temperatures.
  22. If it's jewelry and glaze fit isn't of utmost importance, glaze to the earthenware clay temperatures. Vitrification isn't *as* big a deal for something you're not eating off of or isn't subject to mild acid or base exposure.
  23. Hello, I’m new to ceramics and have been working with some mid-fire porcelain clay as well as white earthenware clay. I made several hundred small jewellery pieces from both clays and had them bisque fired at a local kiln service. Unfortunately they combined all my work together and now I don’t know which is porcelain and which is white earthenware, soI don’t know which clear glaze to use on which piece. Might anyone be able to give me some advice about what I could do? Are these pieces salvagable or bound for the bin?
  24. Last week
  25. I want to refire a piece that has been fired to cone #6. Can I refire it at cone #5?

    1. Min


      Sometimes this works, sometimes not so much. It's a crapshoot with refires but if it's not acceptable as it is now then theres nothing to loose by  refiring it. Cone 5 would be good, less chance of the glazes running and / or bloating with the clay. If you aren't sure how runny the glazes get with a refire then putting the piece on a thin scrap slab to catch any glaze runs is a good idea.

      BTW, this Status Update section is more for what people have going on at the moment, for your question the Studio Operations and Making Work section might get you more replies.

      Welcome to the forums! 

  26. Ok thanks. My plans for burner port is currently 3" X 4" opening. I plan the chimney at 6" X 6" inside with 3" thick walls.
  27. Just to echo what @liambesaw said, there do exist smaller private websites with well-curated handmade craft. https://www.artfulhome.com/ is another one. Artful Home is basically a wholesale deal for the artist, you split the retail cost with them, then you drop-ship the work to the customer. You pay Artful Home much more than you pay Etsy, in order to have your work displayed among nothing but well-curated work. The other well-curated online craft sellers that I know of also work on a 50/50 split. It’s a trade off. If you want something with lower costs like Etsy, you can’t tell them to lower the volume of work. If you want to be seen in a well-curated environment, you need to pay them for the added value of their venue. It's expensive! It should be treated it like a gallery relationship, as in you have to compete to get past their discerning selection process, and give them half of the sale.
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