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About Soren

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    Illinois, USA

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  1. In similar situations, I have had some thick glazes even out in a refire before. It does not always work perfectly, but usually provides some better results. My assumption is that glaze melts a bit more on the second glaze firing than the first. I also have found better results with a slightly higher glaze firing temperature. When I was first experimenting with supporting objects glazed all around, I had some stands that failed and allowed objects to become glazed together. After separating the objects, I ground off the glaze around the separation points and reglazed. After refiring, the glaze formed a sealed glossy coat, but the coloration was a bit different on the repair places. I have also noticed on a few of the glazes I have used that a second glaze fire changes the color slightly. One particular glaze was Laguna's ^06 Danish Blue, which increased in transparency and depth/darkness of blue after two glaze firings, which was I result I wanted. I have not tested it yet, but I hope to achieve the same effect with only one firing now that I am glaze firing to ^04. It also seems likely that a hold after the second glaze firing should allow for more flowing time for the glaze to even out. This worked for me recently when I had bubbles clouding a clear glaze that was applied too thickly.
  2. At this time, I work exclusively with earthenware to maintain porosity in the finished object. I bisque to ^04, as intended for the earthenware clay bodies I use. Before, I glaze-fired to ^06, but I recently have found better results with smoother finish and less entrapped bubbles with a ^04 glaze firing. I brush on the glaze, so application is less even and smooth than dipped or sprayed objects so more time is needed at a fluid state of firing in order for the glaze to smooth evenly. Doubling on ^04 simplifies the necessary cones, since the target cone is the same for both bisque and glaze, which is a nice side effect. The best way to answer your question is probably the simplest answer to say and the most work-intensive to do: experiment with your clay and glazes to find the desired results.
  3. Mason stains are powders that can be added to paints, clay, cement, etc. that add color. They are made up of different elemental combinations that are calcined or encapsulated so that the colors are quite stable and safe for use. For ceramics, they are used as glaze colorants or clay body colorants (best if using a body stain specifically for bodies). See the Mason Color web page for ceramic stains for more information. Many of these are carried by many ceramic suppliers, like the one Rae Reich posted while I typed this. Others include The Ceramic Shop, Sheffield Pottery, and US Pigment Corporation. There are hundreds of possibilities. Search for the one with the best price for your location.
  4. I am pretty sure from the above posts that LonesomeDove found the fuses between the kiln and the main power panel, therefore not on part of the kiln. I do not think the old kilns are built with fuses. For my kilns, I rely on a breaker-controlled power supply for safety rather than fuses.
  5. The first kiln I got (well used and purchased indirectly from a friend of the artist who used it) had breaks in 4 of 5 elements. If you cannot find them visually, you can check continuity with a voltmeter at the points where the elements enter the kiln. Any element with discontinuity is broken. You can also measure resistance if you should choose, which can verify amperage used and heat input to the kiln from each element. Breaks in the elements are certainly a likely issue with old kilns and well-used elements as the elements become brittle after age and use. If you plan to fix it yourself and know enough about electricity, open up the switch box and check that no wires have corroded and lost contact. Sometimes this can be a simple fix with the collar couplings used, as you can just extend the wire further into the collar and reconnect. Replacing the cheap switches like Neil mentioned is also a great start. Of course, all element and wiring work must be done with the kiln unplugged, not just turned off.
  6. Thanks for the recommendation, Neil. Ceramic Supply Chicago does look like a good option for me when ordering clay. I do not have a studio set up yet and am just working out of the end of our workshop at home, so it is probably worth the extra cost for me to buy clay in 50-pound boxes and pay for shipping. When I am set up, though, this will be the place to go for bulk clay. Is there a website that I can view products and prices at Ceramic Supply Chicago? As I find it now, the website says that the webstore is "Coming Soon". I assume they would have anything I would be looking for and that they would likely have a good price, but I would like to be able to compare. As a hobby ceramicist, I like to plan my expenses well. I never noticed before that you are only about 3 hours from me, Neil.
  7. I just had a similar issue to this with a stock Laguna glaze at ^06 (see topic if interested). I cannot say that it is an exact parallel (due to cone difference) but my bubbling issue went away almost completely when I raised firing temperature from ^06 to ^04 and allowed a ~20-minute soak period right after the kiln sitter switch dropped on my kiln. Thicker application of glaze seems to increase the chance for bubbling to be noticeable after firing is complete. Slower firing time may help in allowing time for the bubbles to be absorbed or released during the fluid stage of the glaze. The bubbles got worse on the clay I stained with Manganese Dioxide, which apparently off-gasses even worse at ^04, causing bubbles in the glaze to become extreme rather than eradicated. If off-gassing is your issue, I have no advice how to avoid the bubbles.
  8. Well, after checking out the website for US Pigment Corporation, my search is probably over. They have everything I could imagine needing and are only about 150 miles from home. I do not know what they would charge for shipping, but this is probably the best and most local supplier I have found yet. Unless I can buy materials from the local community college or from another ceramicist or small studio in Peoria, the US Pigment Corporation seems like the nearest supplier with all needed ingredients. Thanks for all the help!
  9. Ha, not really. I am only about 20 miles from Peoria, and I ought to be able to find what I am looking for somewhere there. I just do not know store names. Local potters will probably help here. This is exactly my predicament. As a hobby clay worker, my orders may never be big enough to justify the time and cost of travelling to the store, even if shipping seems expensive. For the time being, I will probably just pay for shipping until I have a studio set up and might consider true bulk orders. Right now, I just work in the end of a shed at home. Thanks, Mark. I will ask Neil. If my work becomes successful enough, I may consider opening a shop in my nearest downtown: Speer, population 25, about 10 houses plus a bank, population doubles when the bank is open! Thanks for these references, Fred. Most of these stores are about 2.5 hours from me, as they are in or near Chicago. I saw the Blick store in Galesburg when I went there recently to buy a used kiln. This store may be a pretty good option, especially if they would happen to carry raw glaze ingredients like frit and kaolin. Also, thanks for the link to the yearbook. This may be a great source of information for me. I have ordered some cobalt carbonate from U.S Pigment Corp. I never realized they were so relatively local for me. When I am looking to purchase more colorants, I will keep them in mind.
  10. Thans, lgusten. I could check at my local community college. I was studying engineering which left no time to take art classes, but I would dream of ceramics when I passed the basement studio on my way to a lecture hall. As a hobbyist, my order list is rarely large enough to make a distanced trip cost effective over just paying the shipping cost. I will have to check into this, Mark. These considerations never came to me before as a small hobbyist, but I should check with the other ceramicists at my local market. They would likely be able to help point me in the right direction for local in-person education and materials. My commitment level to ceramic work is increasing, as are my expenditures there, but I do not plan to quit my engineering job to work ceramics full-time. Local ceramicists should have been my initial go-to, even before I posted this question here.
  11. So, should it work to calcine the MnO2 above 1976F to convert it to MnO and make an effective stain that does not off-gas so badly? Oh, this is a great help! I knew I could get the same results if I mixed my own glaze by measuring water and ingredient amounts, but I had not considered specific gravity to check already-mixed glazes. I will also be using specific gravity for terra sigillata, so I will start to keep the specific gravity records on glazes as well. Thanks for the help, Min!
  12. Apparently I was not clear enough in my title and original post (which have been slightly edited). I do not want to buy "in bulk", but rather would like to find a local supplier that has bulk and redistributes materials. My interest is in 50-pound boxes of clay and 50-pound bags or less of select dry materials such as in the above list. Thanks for the response, Mark. I have tried to search for ceramic supply stores, but I am having trouble distinguishing what stores would actually have bulk supply that is portioned in quantities near my interest as a hobby ceramicist. It would seem from the searching that the likeliest spot to find a store would be Chicago, which is 2-3 hours away from my home. If that is the case, shipping cost is actually cheaper than the cost of gas as well as time spent travelling. After considering, I know an obvious route to take to find what I am looking for: talking to the other ceramicists at my local market. They would probably know the best suppliers, as they are professional ceramicists. This should have been the obvious first route for my questions...
  13. I do not know specifically right now, and not everything do I want to buy in large bulk. The main items I am interested in right now are Standard 100 clay and dry glaze ingredients such as Frit 3195, EPK (Kaolin), dolomite, Gerstley Borate, calcium carbonate, etc. Clay would be purchased in larger lots, but I would like to buy some of the glaze materials in portions measured from a bulk supply. No, I was searching for ceramics suppliers or bulk materials stores rather than the specific items. I will try searching for the specific items in my location and see what I come up with.
  14. Does anyone have recommendations for finding local bulk suppliers for materials? (Edit: I want to find a supplier with bulk quantities where I can buy materials by the pound, not by the ton or other large bulk) Online orders work fine for most things, as availability is high, but shipping costs can be inhibiting when the cost is about $1 per pound. How do I determine what materials a store has before travelling there? Do you recommend certain store chains? How do I even research local stores that are not chains? I know this is a very broad question that I may be able to answer for myself with enough research. I live in central Illinois, about a half an hour from Peoria, if this helps with specific recommendations.
  15. Yes, there are definitely more bubbles in the double layer, which seems to link the bubble issue to thicker application. I think the glaze has lost some water which has thickened it, causing my usual method of brushing to apply a thicker coat this time. This is the first time I am using the clay with stains and oxides, though I have used this clay before. The same bisque and glaze firing schedules were used before, though this is the first time in the current kiln (which is a very similar type to my old kiln, though dial-operated with relays instead of simple element switches of the older kiln). The glaze has never bubbled like this for me before. I did not communicate this well: my test kiln is very similar to both of my other kilns, both in size and type. The test kiln is just my oldest kiln and the one I did all my learning in (hence noticeable visual damage inside due to dripped glaze and items that fell and glaze-fired to kiln bricks, though function has been fully repaired after my many beginner mistakes). I have not used this kiln since I got my two newer kilns recently, but I intend to test glazing methods in this kiln to avoid damaging the newer kilns. This probably concerns the placement of objects more than firing range/schedule. I may use the old kiln as my glazing kiln to avoid any glaze damage to the newer kilns. Thanks for the tips, Min. I will try this next time. I will give this glaze a try. ----------------------------------------------------------------------------------------------------- The results of the ^04 glaze firing were interesting. Most of the test disks resulted with glaze that cleared up and smoothed out better than before, as seen in the examples on the right of the next image. Some tiles got much worse, as seen on the left in the next image, to the point that the bubbles crackle (audibly!) if I touch them. It would seem that the ones that got worse were the ones containing manganese dioxide, so I am assuming that manganese dioxide gases quite a bit, especially at ^04. I think I have read in another thread that this is the case with manganese dioxide. Is it possible that the gases from the manganese dioxide would affect the other tiles in the same firing? I fired all the test disks together for bisque ^04, glaze-fire ^06 ,and re-glaze-fire ^04 (probably around 100 disks ~1" diameter of different colors and concentrations). Double thick coat of glaze still seems to be too thick and is still slightly bubbled on all disks, but the single coat seems to give the results I want.
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