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  2. This is an old post, but it remains relevant. I charge by the # of fluid ounces the mug/vessel contains: 1-8oz $15; 8-12oz $20; 12-16oz $25; 16-20oz $30. (with occasional $5 off sales). The pricing theory is pretty obvious. The more ounces, the larger the vessel. The larger the vessel the more clay/glaze needed, plus fewer per kiln load. Note: I also use color coded price labels: Yellow, Pink, Green, Orange (attached to bottom of each mug). A tabletop sign indicates pricing for each coded color. This allows me to easily change prices when needed without have to change labels.
  3. Very cool, thanks! Haha yeah, glad I'm not crazy. Ah great find. Somehow missed that in my glazy digging. Without modifications it calculates out to 6.2 COE, so it looks like a good start. Good advice. I'll try this with each of my 'flux' attempts. I don't have access to 3249, or any other MgO frits (I'm sure I could get it, but the local supplier doesn't stock it). I think I might formulate something along those lines with 3124 and talc though. If this all works out I might order a magnesium or lithium frit to experiment with. Haha, I was afraid someone would ask. There isn't a good answer, and I'll probably switch to ^6 at some point. But for now the firing cost isn't significant, and my tiny kiln has no problem reaching ^10 with power to spare. I do have a few reasons why I started there, the main one being I learned at ^10 because that's what the local community centre fires to, so it seemed like a comfortable starting point. Also, my work is slipcast translucent porcelain, and my local supplier has the most selection of ^10 porcelain clays. Last, I wanted to formulate my own glazes, and more raw materials melt at ^10 so it was a bit easier to learn the chemistry.
  4. are your current shelves going to be used in the new kiln? if so, check that finger width spacing. with gloves on, it is sometimes hard to get fingers under the shelves in my 3 inch brick kiln.
  5. A 'clay body' is a blend of clays and other ingredients that make a workable mix. Porcelain, for example, is kaolin, feldspar, and silica. What you're dealing with is just a single clay. Personally, I couldn't even venture a guess as to what it is without actually touching it. Have you processed the clay?
  6. You have to broaden your view of what the customers are really buying. It's not just an "ornament". I sold 30 something of this last week to a customer from Canada. She made a "list" of all the people she wanted to take "a little happy to" (cat sitters, plant waterers, grandchildren, nieces/nephews etc). Last summer someone ordered 450 of them to give out at a lady's conference. She was the president of the Mississippi chapter and saw them at the only show I do in the Spring. We didn't sell but 50ish at the show but the idea was planted for later. You can just as easily sell that angel or cross as "a little happy". Of course I add a little packaging that enhances gift giving. It's July but a customer may think "that's a beautiful handmade gravy boat. I could give that to my 2 daughters and daughter in-law for Christmas. I'll take 3 of those. No wait. Give me 5 of them. I'll give them to my sister and sister in law too." A "heavy sauce" NEVER comes to mind. I would sell more during 4th quarter because I sell more of everything then, but I never rule out an item because it's not 4th quarter. Of course I will sell more of those "ornaments" in Nov/Dec but they are buying some right now.
  7. Yesterday
  8. Sounds like a good plan. I would also try a magnesium fluxed clear, this one from Matt Katz could be a starting place. Play around with the recipes in Insight to get the COE down to the low 5's while keeping the silica:alumina ratio the same (and keeping an eye on the limits so you don't have a crazy high amount of something). Run a progression line blend of the lowest calculated COE glaze and the same glaze with the highest COE you are interested in testing, somewhere along the line there will be one that should fit. COE figures are the most useful when looking at a glaze then without adding or deleting one of the materials just changing the proportions of the materials. If you do want to try a boron frit and have access to Ferro 3249 that would be a good choice. It a low expansion frit that supplies boron and also magnesium (along with alumina, silica and a bit of calcium). Try using Insight and adding around 5% of it to any of the recipes above then rebalance them and see what it does to the COE figures. Just have to ask, why ^10? Is that the only cone you have access to fire to in a shared firing?
  9. Hi Kathy, I'm in Chicago and have been looking for a kiln. Could you please send me the interior dimensions? Info is quite hard to find online. Also, if you could, send a bigger photo or just transcribe the electrical info. Can't quite make it out in the picture. With more info, I may be able to pick it up this weekend. Also, I will run the wheel by my studio mate. She mentioned wanting a wheel when I was getting the place wired! Thanks for the info! Derek
  10. Hi MFP... i just got an 2831 with four burners, propane. Yesterday I did my second burn and have not yet seen its results. I burn at ^6 but am in my way to ^8. My objective is to develop and work mainly with natural glazes. First burn was uneven. Bottom shelf did not reach temp, probably below ^5 since glazes did not mature; top shelf reached ^6 and pieces were fine except one large vase that received direct flame and left a black spot on the side. I contacted Olympic staff hoping to get some advice and received no answer at all. I began to look at this forum and here I am I use 45 kg propane gas tank, conversion is about 12 gallons. So far two burns and there is still gas in it (probably around 20 to 30%). In first burn I bent over to load it and was quite uncomfortable. For this second one I took out the cover and first two rings, much better. First shelf at the bottom is on 3” posts as recommended by Olympic. On this second burn I did put cones all around to see cold/hot spots, also, changed the location of the shelves, used them as barriers to redirect flames and get an even burn. By the end of the week I should know how it went. Also, did my first reduction burn, very excited about it.
  11. The last thing I was working on is a bubble free transparent. It's a slightly odd recipe as I was trying to remove any silica or clay. I was also removing zinc because I hear it is bad with some colours, and I don't know how well it reacts in reduction firings. Fired to cone10 oxidation on the tile. It is true that you don't need boron at cone10 but I see no negative reasons not to include it. I think your observation that a lot of the recipes are probably more a cone11 is a good one.
  12. Ceramic workshop with textural tile maker and sculptor, Rhoda Kahler. Stamp it, sculpt it, carve it, keep it decorative or make it functional! July 25 & 26th, 10am - 4pm Opportunity to make either two tiles or one tile and one sculpture included in the price. (Tile size approximately: 10”x10”) Lunch will be served both days during the class, this is included in the price. Students do not have to bring any materials but are welcome to bring their own texture materials and/or sketchbook/notebook if they’d like. This class is great for students that have worked with clay before but beginners are welcome! Students do have the option to make the second class focused on tiles if they prefer. Students that create more than the two items described above, can purchase additional tickets at the front desk. $225/$200 Members Space is limited, registration deadline: July 17th, 2019 Click Here to Register Class will be located at: View 3272 St. Rt. 28 Old Forge, NY 13420 www.ViewArts.org 315-369-6411 Rhoda Kahler’s Biography Rhoda Kahler is a ceramic artist with a studio in West Chester, Pennsylvania. Her work has been featured internationally, nationally, and regionally in magazines, newspapers and television, including on the Home and Garden Television network (HGTV) and Crave Magazine, among many others. In addition to exhibiting in galleries, Kahler’s large scale handmade tile murals and sculptures appear in public and private collections. Notable commissions include the Delaware Art Museum, West Chester University and the Philadelphia Environmental Film Festival. Kahler conducts workshops nationally and participates in a wide range of Artist Residencies, some of which include the Philadelphia Museum of Art and Inglis House. Kahler is an adjunct faculty member at West Chester University, where she received her bachelor of fine art degree in 1995. Drawing from nature, much of Kahler’s art bends toward the organic, making use of abstraction and assemblage. There is a tactile intimacy that is translated through the mud between her fingers to her pieces that beg to be touched. Kahler is captivated by surface and in a never ending exploration of the vast textures that can be achieved through clay. The majority of Kahler’s work is cone 6 oxidation however, pit firing techniques and photo lithography were used for the 24/7 Project.
  13. I'd like to know if the clay I dug from a very Rocky local Indiana creek is pure kaolin clay. Its a solid gray in color, and after storing it for a year, it didn't even mold. Other light brown colored clay from the same creek had molded. I know moldy clay after aging improves elasticity. This gray clay looks and feels like pure clay of some sort. I know this clay came directly from the source ( huge rocks , nothing but rocks. Would it be a porcelain clay body?
  14. Would you be willing to share an example recipe? No worries if you would prefer not to of course. I'm struggling with a starting point because most people say you don't need boron at ^10, so there isn't too much info about it. So far I think I'm going to give all three suggestions a shot. Adding alumina + silica to a basic ^10 recipe, adding Li2O in varying amounts, and using a boron frit. It's easy for me to make up a ton of tests, not easy to fire a bunch of times.
  15. Thank you for this, it's extremely informative. The way that I thought the hold worked was to make sure that the temperature stayed on the desired cone for long enough for it to have an affect, if that makes sense. I didn't realise that it goes up a cone by roughly 20 minutes at a time, which just goes to show how little I know - I will glady admit that I am very uneducated about ceramics and have a lot to learn. I've been doing a lot of research all day to try and fully understand why this might have happened, and if we can go back to absolute basics for a second, how can we know how to get a good 'fit' with bisque and glazes? The earthenware slip I'm using has a firing range of 1080 - 1140 C, the Amaco Underglazes can be fired between cone 05 and cone 10, and finally the transparent gloss overglaze I have been using has a firing range of 1000-1140°C . Given that these ranges cover up to three different cones each, how do I know which cone is best for each firing? From my understanding, the bisque firing must always be a higher temperature than the undeglaze and overglaze firing, is that correct? So how much of a difference would it make if I fired the bisque on cone 01, 02 or 03? Or is it simply a matter of making test pieces, trying out different combinations and seeing which renders the desired result? I have been reading that crazing can still happen months later if the clay body and glaze are not a good 'fit' for each other. So I suppose I'm trying to work out how I achieve that perfect fit in my firings in the future? Finally, I think I may have worked out what when wrong with these particular pieces. My guess is that the bisque was not fired high enough, and that when it was removed from the kiln and began absorbing moisture from the air, the clay expanded and put pressure on the glaze. I guess this because crazing has never happened with pieces that I fired on cone 01 in the past. Also, if the firing temp of my clay slip is 1080°C-1140°C, am I right that 1080 is cone 03, and therefore cone 04 would not make the clay hard enough? It seems in general that bisque is fired between 04 and 06, which is why I got very confused. My friend recommended that I fire to cone 04 to avoid crazing, but it seems that with the materials I was using it really didn't work. Furthermore, in the Q&A section for this overglaze on Scarva, there are lots of people having problems with this glaze crazing on Earthenware. Scarva's response is 'Earthenware glazes are prone to crazing due to not fitting the clay body. Sometimes it is possible to do a high bisque and low glaze but then it can be difficult to get the glaze to fit the clay body. For functional pieces it is much easier to choose a stoneware clay body and stoneware glazes then it is possible to do a normal bisque to 1000oC and high glaze. Hope this helps.' This is a really good idea, I will definitely try this with one of the pieces. The overglaze says it will fire up to cone 01, so it might work. The only problem is that some of the underglaze colours might burn out a bit.
  16. I like using a boron frit at cone10. Much better than using zinc as a flux.
  17. Yep, lots of successful low expansion glazes that use sodium, calcium, and potassium. Interesting dilemma so my suggestion is find something that works with a durable flux ratio and adjust out the crazing. Pretty easy to do a clay silica progression in one test fire. If the glaze ends up in slight tension it strengthens your finished product (we know this from testing) so adjusting till it’s gone is an easy way to sneak up on this point. Not too difficult to take 100 or 200 grams of glaze and progress it through 5 -10 variety’s with simple Clay and silica all in one firing. If it works, super simple easy method. Now with respect to eliminating crazing in a true matte, a bit more difficult. Seems you have done a bit of testing and firing already and have glazes with marginal R2O to begin with and still craze.
  18. Thanks everyone for the help. I see your point about the flux ratios, but I'm having a bit of trouble understanding how to get good flux ratios but low expansion. Low expansion seems to mean dropping as much of the KNaO as possible, but that also drops the flux ratio out of the 0.2:0.8 range if taken very far. Am I missing something here? I know boron isn't needed at ^10, but cost isn't really important here so I was thinking a boron frit could provide a bit more flexibility for adjusting melting in my base recipe. One other thing I noticed is a lot of ^10 potters are firing in big gas kilns with long cycles and soaks, so lots of "^10" glazes don't seem to melt particularly well until the bottom of ^11. That's fair, but unfortunately can't fire that often, so I think it's a valuable starting point. I use it mostly as a method to guide my testing, not the end-all. Thanks Min! Do you change KNaO for Li2O on a 1:1 molar basis? Or just aim for something close and adjust with testing? Would you prefer Li2O over boron? I use Insight. Your pictures are familiar haha :).
  19. Next time you do a cone 01 firing of the bisque put one of the glazed pieces in the kiln with a thin wafer of clay under the piece to catch drips, in case the glaze runs, and see how it does. Your glaze might be able to go to the higher cone in which case the pieces could be re-fired. The clay will likely be okay but it's a question of if the glaze can take going that hot without issues.
  20. Sure, I completely destroyed my first set of kiln shelves. They are now recycled as raised bed planters. I don't do much porcelain, when I do they're either on a slab of soft brick or I dust the shelf with alumina. Student work requires a whole different level of fore thought and protection. I spent a bunch of years in what was basically an open studio, or anarchy central, as I liked to call it.
  21. Cones measure heat work, which is temperature over time. Holding temperature has the same effect as firing hotter. In general, a 20 minute hold will get you approximately one cone in added heat work. So a 45 minute hold equals roughly two cones, which would put you at cone 2. The 20 minutes is not exact, though, so it's hard to say just what cone you were firing to. The hold on the 05 glaze firing also means that you're getting to a higher cone, probably more like 03. I would either stick with the schedule you know works, or do a firing on that schedule but put cones in the kiln so you can find out just what cone you're actually getting to. You don't have to be able to see the cones during the firing, you can check them when it's cool. Once you know what you're actually getting you can just fire to that cone instead of using the hold. Or like I said, just stick with what you know works, although you're probably wasting electricity with those long holds.
  22. Please can you elaborate? As I said I am relatively new to all of this. I wasn't having problems on cone 01 with 45 minute hold. I still have pieces which I made in November of last year using those temps, and they don't have any crazing.
  23. Advancers or bonded nitride can stick to some fluxed porcelain so I have seen folks use something like Lees Kiln wash on these to keep the fluxed clays from sticking. As far as mullite in the studio, students often glaze with a certain flowing creativity in mind so these drips can be pretty significant and eat through enough of the wash to require grinding.
  24. @JohnnyK - we've walked the same roads...except for the farming part. But I understand the "hand work" and the ability to see underlying structure. Got a great book you might be interested in - Shop Class as Soulcraft by Matthew B. Crawford. I think you'll enjoy it. He had also written an essay for The New Atlantis that preceded the book - https://www.thenewatlantis.com/publications/shop-class-as-soulcraft - Jeff
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