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Rockhopper

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  1. Rockhopper

    Need your opinion on 1-phase electric kiln

    Same in the US... And, as Bill suggests - based solely on the wattage ratings you gave, the 3-phase would get hotter and/or heat faster. The most important question is: Which version matches the wiring available where you plan to use it ? If the location you're going to use the kiln is only wired for single-phase, the three-phase version won't work.
  2. Rockhopper

    How to duplicate this?

    Amaco's website has both written instructions, and a video demonstration of brushing technique, here: https://www.amaco.com/t/glazes-and-underglazes/high-fire/potters-choice. Scroll down, past the first set of color tiles, and you'll find "Application Instructions for Brushing". It doesn't give specific details for the particular combination you asked about, but it is a good general guide to applying the PC glazes. And, on this page: https://www.amaco.com/products/glaze-pc-36-ironstone?ref=2&taxon_id=273, where they show various layering combinations of Ironstone over, or under, other PC glazes, it says "Here are some examples of PC-36 Ironstone over some other Potter's Choice glazes (2/2 coats fired to cone 6 on AMACO's #46 Buff Stoneware)" "All" you have to figure out is how thick to apply each coat, what firing schedule to use, and where to place it in your kiln - that's where the "test, test, and test again" that you see throughout this forum comes in.
  3. Rockhopper

    How to duplicate this?

    Looks to me like the glazes may have been applied - and then most of it wiped off of the raised portion of the 'flutes', leaving thin coat of the ironstone around the rim, and much thicker below the rim. The universal disclaimer "individual results may vary" is definitely at play here. Aside from differences in application thickness, the composition of your clay body and firing schedule will all affect your end results. I've tried a number of the PC layering suggestions on the Amaco website. Some have come pretty close to their sample images - others don't look even a little bit like them. (In some cases, I liked mine better. In others, not so much.) I think most of their examples are using a buff colored clay, and someone told me they actually fire to cone 5 with a 15 minute soak. If you're using white, or brown, clay you'll get different results. If your clay has significantly more (or less) iron than their sample piece, it will be different. If your firing schedule includes a longer - or shorter - soak time at the end, your result may be different. A pot fired in the top of your kiln may look different than a pot with the same combination, fired in the middle or bottom.
  4. Rockhopper

    Glaze on bonsai pot foot

    On a pot like the one in your picture, I think I would just leave the entire foot un-glazed. There's a fairly distinct line where the pot ends and the foot begins, so should be pretty easy to get a clean edge, and have the glaze stop at along the same line.
  5. While it would probably work to keep your water warm... it sounds a bit risky. Most aquarium heaters are a thin-walled glass tube with a heating element inside. If the glass cracks, water could get inside, and create the possibility of electrocution (or at-least a shock) when you stick your hand in the water while touching anything that's grounded (like a metal wheel head). That's why most of them will have a warning somewhere in the instructions, or on the heater itself, to unplug before sticking your hands in the aquarium to clean it. In theory, if everything is plugged into GFCI outlets, you would be safe, but I think Min's crock-pot idea would be much safer - and more durable.
  6. Rockhopper

    yarn bowl dilemma

    Are you certain you're not over-firing ? Could just be the nature of the glaze - but it looks like, in addition to the clay sagging, there's a lot of running in the glaze. The smaller scroll to the left doesn't appear to have closed up very much - but the channel is almost completely filled with glaze. The bottom of the curve to the right, where you had the wedge in the top picture, also looks like the glaze has run/sagged - like an overly thick coat of paint. Have you had the same issue with other glazes ? What about firing one un-glazed, using your glaze-firing schedule ? There are plenty on the forum much more expert than I on clay/glaze interaction - but some glazes will interact with the clay body, over-fluxing it, and causing it to move a lot more than it would with different, or no glaze.
  7. I got a similar effect once by putting a bowl on the wheel, held in-place by some coils, as you would when trimming, letting it turn at a low to medium speed, and pouring some glaze into the center. Like the 'spin-art' done by pouring paint onto a spinning sheet of paper. (Here's a small version on Amazon: http://a.co/d/6oZ09OB )
  8. Rockhopper

    Hudson River Clay

    Oh, I have no doubt of that. Chased him a long way down that hole before finally giving up when I reached the point where my creek clay was just another ingredient in a mix that was 60% 'other stuff'. It wasn't totally wasted effort - I did manage to get a couple of usable flower pots, and learned a lot along the way. Unfortunately, $500 is way beyond what I can afford right now, so I guess I'll just leave my bucket in the corner of the basement.
  9. Rockhopper

    Hudson River Clay

    Where did you send it for analysis ? And, if you don't mind, what did it cost ? I have a bucket of clay I dug from the creek-bed where I grew up. Experimented with it off & on for 2yrs, trying to get a usable ^6 body (or glaze) from it, by mixing with various combinations of EPK, Feldspar, OM4, and other things that were available to me at a local studio. Have always wondered, if I had it analyzed, would I be able to use the report as the basis to formulate a successful blend - but never found a place to have it tested.
  10. Rockhopper

    Plaster for wedging table

    I hope you have a VERY sturdy table. If I pushed the right buttons on my calculator, your slab will contain 3.4 cubic feet of plaster - which the charts at sculpt.com, indicate will weigh nearly 375lbs wet (depending on mix ration), and over 300 lbs dry. Instead of pouring large, thin layers, you might want to consider doing it the way they pour concrete highways: divide your table into sections that you can fill with a single 'batch', and pour each section full depth. (Use a piece of plywood, or a 1x4, etc.). Advantages of sections: If an area gets damaged, you can replace just that section... and, if you ever want/need to move the table, you can move it in pieces - like they do pool-tables - instead of trying to move one giant 300 pound chunk.
  11. Rockhopper

    Paragon LT-3 Kiln Over Firing

    I would check with an appliance-parts store for high-temperature wire, if your pottery supplier doesn't have it, or you're not able to get it from Paragon. A "big-box" (THD, Lowes, etc.) might have it in the appliance department - but the wire they usually have in the electrical department is going to be for normal building wiring, with insulation rated at 90*C (or less). "High-temperature appliance wire" is usually in the range of 150* - 250* C.
  12. I mentioned this before, but did you try drilling a hole in the bottom of the dish ? If air can't get in, the plaster's not coming out, no matter how hard you pull (at-least not in one piece). It's the same effect as a suction-cup firmly pressed onto a mirror or smooth piece of metal: If you pull on the center of it, it's going to stay - but if you slip a fingernail under the edge, so air can get in, it will pop right off. What are your 'forms' made of? If they're plastic or metal, you should be able to drill a small (1/8") hole that will let air in, but not prevent being able to use it again as a mould by covering the hole with a piece of tape on the outside. Something else to look at: Are you certain the sides are 'straight', and not tapered inward ever-so-slightly ? If it's even a tiny bit narrower at the top than at the bottom, you're fighting a losing battle - even if you do get air in from the bottom.
  13. Yes... for the same reason you can't throw a piece to the desired finished dimensions. If you make the mold from the finished piece, then the pieces you make from the mold will be smaller, by whatever the shrinkage of your clay is.
  14. Could be they're "vacuum locked". In order to get the plaster out, air has to get in. With sloped sides, as soon as the plaster moves even a tiny bit, it separates from the sides, and air can easily get past it into the dish and break the vacuum. The straighter the sides, the farther it has to move to reach a place where the plaster is narrower than the dish, so that air can get in. The mineral oil may actually be working against you in this situation, as it creates a flexible seal between plaster & dish. If you're not up against a deadline, you may find that just waiting a day or two will give the plaster time to shrink a bit as it dries, and create the needed gap. If you don't care about the dish, drilling a small hole or two in the bottom might do the trick.
  15. Rockhopper

    What’s causing this crawling?

    Looks like you're copying and pasting "thumbnails", rather than the actual images. I see a "Photofy" watermark at the bottom corner. I'm not familiar with that app/site, so can't offer much help in getting the full-size pictures... maybe there's a "share" button that will generate a link - or, maybe you can upload directly from your computer (or device you took the pic's with)
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