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Min

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Everything posted by Min

  1. Cone 6 matte glaze that I use a lot of is a blend of this dolomite matte one plus my clear. I find it does cutlery mark without a bit of clear mixed in with it. The Ferro frit 3249 is silly expensive, there is another version of the glaze here without it. I use the 3249 version as I find it melts better. For whatever glaze you use if you find the specks don't run enough decrease the clay content (usually epk) until they do. Take note that this might increase the chance of crazing but this glaze uses low expansion materials so it would probably be okay. Add zircopax or tin or a combination of both to make it white. BTW in oxidation firings such as in an electric kiln the speckles will be from granular manganese dioxide not iron.
  2. @LisaJJ, when you look at the cone chart Bill linked to be sure and read the blurb on the right side and note that the speed of the firing makes a difference to the melt of the glaze/cone. For all firings the heat rate for the last 100C is important to note. If you are interested in more reading Orton has a wealth of info on their site. (nice to see someone here from Wales! My dad and little sister were born in Llanelli)
  3. Yes they are! I bought a used one from Pottery Supply House (aka Euclids) in Ontario a couple years ago. I'ld give them a call and ask if they have any if you decide to replace it, if you have wiring questions ask to speak with Jay Clarke. Their shipping is $12.50 if it fits in a clay size box.
  4. @LisaJJ, are you firing to earthenware or stoneware temps? One other snippet about conditioning elements, this one from Euclids which is a company that supplies kiln elements to many manufacturers. With all due respect to Bill I disagree about only needing to keep the spyhole plugs out for the first four hours. "Why and how should I pre-oxidize my elements? 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 exposed to any harmful atmospheric conditions. This procedure is usually only done once, but can be repeated as required if the kiln is fired under harsh conditions such as a reducing atmosphere (which actually removes the protective coating)." And from the link from Skutt that Bill provided: "4. Vent! Vent! Vent! Even if you have the best oxide coating ever, the fumes that emit from clay and glazes can still attack the element when it expands through heating and forms cracks in the coating. Downdraft vents are your best defense against potentially harmful fumes. Downdraft vents pull the fumes from the kiln chamber before they have a chance to damage the elements. If you do not have a downdraft vent your next best option is to prop the lid a couple of inches until the kiln reaches 1000 F to allow the fumes a path to flow out of the chamber. You should also leave the top peephole out during the entire firing to handle those fumes that escape above 1000 F."
  5. @blackthorn, your ^10 cyanotype + white underglaze looks like fossil dug up from an excavation. Neat stuff! Thanks for sharing your process and results.
  6. If it's a brand new kiln with new elements the first firing should be a slow bisque firing with the kiln empty and all the spyhole covers out (if there is no vent on it) to whatever cone or temperature the manufacturer recommends. You want any moisture, machining oils etc to be vented plus for the elements to oxidize to build up a protective layer.
  7. And if the building burns down? It's uncommon for there to be a fire from an electric kiln but it does happen.
  8. If you go this route there is a really good article here about converting an electric kiln to gas, covers burner ports, draft, flu etc. Finding some trashed kilns right now is going to be the hard part, used equipment is getting snapped up really fast due to the pandemic.
  9. I would also run this idea past the studio manager for insurance purposes.
  10. With the power off does the pedal move smoothly? It might be that it's just new and sticky / binding temporarily. Like Mark I haven't used one of these wheels, hopefully someone will chime in here that has.
  11. For soda, salt and wood firings wadding works great to keep the pots from sticking to the shelves. Don't see why it wouldn't work for your mugs also if the wads went on areas without the fluxy underglaze. 3 wads total, 1 on the base under the handle for stability then 2 more around the edges. If the underglaze is fluxing enough to stick to the shelf then I would be concerned that the alumina kiln wash or just dry alumina hydrate will stick to the underglaze which would make a sandpaper rough surface.
  12. I'ld email Amaco and ask them what they recommend as a substitute. customercare@amaco.com I found a few places online that still have it in inventory, here , here and here. (twice the price at the last link in Canada) Welcome to the forum.
  13. If you are making work for yourself and have control over what goes in your pots then the risk of leaching into dry foodstuffs is going to be pretty remote. I think there are a couple issues that come up if you are selling or gifting your pots though. First off once the pots leave your hands you have no control over what they will be used for. You might sell something with a specific purpose in mind but the end user could very well have other uses for it. Your pasta/rice keeper could be my pickle crock. Spice jar for chili crisp etc. Another consideration would be a customers perception on the food safety of your work if they see a copper matte liner glaze (as an example). That being said we don’t know what you use for a liner glaze, there might not be anything of concern. Clear or white liner glazes when fired to maturity are a simple solution. If you mix your own glazes you could post the recipe(s) here so we could offer opinions on it. If in doubt run a couple tests for leaching, what they do is rule out any non durable glazes. If they pass this but you are still concerned you could have them lab tested, cost is about $30 for testing for one oxide.
  14. Just to add a couple points to what has already been said by Callie about glaze fit. If the pots are only glazed on the inside (as seems to be the trend the past few years) this will exacerbate any glaze fit problem insofar as the pots dunting like you are experiencing. Going forward I would test for dunting by freezing half a dozen or so cups overnight then place them in the sink and immediately pour boiling water into them. If the glaze has too low a coefficient of expansion (COE) you will see dunting. (pots splitting) A low COE glaze is one where the glaze is larger than the pot it's on. Shivering (sharp slivers of glaze coming off the pots, usually on the rim) and dunting can result if the mismatch of fit is more than the clay can absorb. Crazing is the opposite, the glaze is smaller than the pot and needs to stretch to fit the pot as it cools. Welcome to the forum.
  15. Very little shrinkage between bone dry and bisque so it's probably okay not bisque firing it if you were just going to ^04 but since you bisque to ^1 there probably will be more shrinkage so to be safe I'ld bisque it. Measure it before and after bisquing so you know for next time what the actual shrinkage is. That's what I would do. Grog or sand will help the slab move on the shelf so yes I would. Some people use even coils of clay spanning the base of the work, spacing them fairly close together instead of waster slabs and grog (or sand). Welcome to the forum.
  16. Just a wild guess here but could the "D" in "DL" stand for dark and the "L" for a colour? Mason Lavender maybe since it can come out pale soft blue if the glaze doesn't have a high amount of calcium in it. Did you ever have that or Mason Dusty Lavender?
  17. If it's an unfired kiln it is really unlikely the elements would break during the move. It's simple to remove the tc's if you are worried about them breaking the weld at the tips. Yeah, it is a pita moving kilns. If they don't have a forklift how are you getting it into the back of your truck? Ramp?
  18. @Steven Goldate, the person you are asking the questions to, @why_not hasn't been on the forum since 2018 so it's unlikely they have seen your post. You could try sending them a message, they'll receive an email that they have a message from you via the forum. To message them click on their screen name or avatar, this takes you to their homepage, from there click on the envelope icon near the top of the page and follow the prompts. (to see when a member was last logged in on the forum just hover your mouse over their screen name) Saggars were traditionally used in fuel burning kilns to stack pots within thus avoiding the need for kiln shelves. They also prevented unwanted deposits of ash etc from being deposited on the pots. For using saggars for localized reduction in an electric kiln your main concern in regards to the kiln is keeping the reducing atmosphere away from the kiln elements. Running a kiln vent will help with this as will using as little in the way of combustibles as possible to achieve the results you are after.
  19. Hi Jennie, Kiln itself looks like the bricks are in decent shape, which is a big plus for it. I had one of those early Perfect Fire controllers when they first came out, not really a huge fan of it. I could only see one image, that of the inside of the kiln, the controller and a couple printed pages I can't make out. Try emailing the photos to yourself to resize them then try posting them. For functional ware it's a fair bit easier to work at midrange temps, in the cone 6 range, than lowfire. Lowfire clays typically have fairly high absorption rates which means the glazes have to fit the pots really well, with no crazing, and ideally the glaze should cover the entire surface of the pot which means firing on stilts. By choosing a midrange claybody with less than 2% absorption you don't have the porosity/absorption issue. This means the pots shouldn't weep, take up water from use (and cause glaze crazing) or get excessively hot in the microwave. There are pluses and minuses to both low and midfire.
  20. Another vendor one is when they ask for a vendor discount like it's common practice to do so. That too gets a "nope".
  21. Have to say I haven't had many customers over the years who have been difficult or rude. Maybe I'm just super fortunate but I find my customers (and looki-loos) really lovely people 99.9% of the time. While the somewhat difficult comments are rare I find there are 2 main categories of them. First are from people who think I will reduce a price down if either they a) pay cash or b) buy more than one of something. My reply to a) is "No, price is the same so it's fair for everyone." I don't get into what is legally required because there always will be people who skirt the rules and I'm not about to start a debate about it. Reply to b) is "I'm afraid I can't do that, it takes me just as long to make pot number 4 (or whatever) as it takes to make pot number 1." I've lost maybe a couple customers by not giving a volume discount but the vast majority of people understand when I give my explanation. If someone is pleasant and does make a substantial purchase I gift them a small item but it's my choice to do so, not a given. Second category of somewhat unpleasant comments are the ones from misinformed people, most often making attention seeking comments loudly to their friends. These comments are along the lines of it isn't safe to use brightly glazed pots because they contain lead or you can't put handmade work in a microwave etc. For these type comments my reply depends on whether they are saying them while leaving my booth or in my booth. If it's the former I just let it go, if it's the latter I politely inform them of the facts as they pertain to my work. I tend to give short and concise replies to loud attention seeking looki-loos as I've found it's rare they actually buy anything.
  22. Have you seen the work of Les Manning? He did landscape type thrown sculptural pots that were mimicking layers of geological formations using heavily grogged clay combined with porcelain and everything in between. I went to a workshop of his years ago, slow drying was something he really stressed. (picture of one of his landscape pots below) If the only difference in process between these cups and your test pieces was the application of the medallions I would be looking at that.
  23. Yeah, I figured they would be but just trying to make the point that bisque firing upside down with the rims on the kiln shelf is less problematic than glaze firing like that. (like butter dish lids sometimes are)
  24. Yup, unfortunately that's always been my experience. There isn't a lot of shrinkage that happens between bonedry and bisque so the drag of the rims on the shelf might not have been the culprit. From bisque to a cone 6 glaze fire firing on rims without a waster slab can absolutely cause rims to go out of round. Do you flip them over to dry the bottoms prior to putting handles on? If so were the rims still fairly soft when you flipped them? Was there a draft while drying?
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