Jump to content


  • Content Count

  • Joined

  • Last visited

About Rockhopper

  • Rank
    Advanced Member

Profile Information

  • Gender
    Not Telling
  • Location
    Southwest Ohio

Recent Profile Visitors

The recent visitors block is disabled and is not being shown to other users.

  1. 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.
  2. 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.
  3. 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.
  4. 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 )
  5. 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.
  6. 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.
  7. 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.
  8. 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.
  9. 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.
  10. 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.
  11. 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.
  12. 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)
  13. Rockhopper

    Pottery wheel belts

    I've not had to replace a belt on my wheel, so don't have experience specific to that, but there should be no reason you have-to buy the belt from the wheel manufacturer - if you can find one elsewhere that's an exact match. If you go to an auto-parts store, take your old belt with you, and ask them if they can match it. There are several aspects to compare, and you'll need to match all of them: In addition to length, width, and number of grooves - the spacing and depth of the grooves, and the overall thickness of the belt are also important. If the belt is too thick, it may not bend sharply enough to go around the relatively small drive pulley on the motor. Other possible sources might be an appliance parts store, or industrial supply. It is unlikely that Brent, or any wheel manufacturer, uses belts made exclusively for them. Often, a belt will have the manufacturer's name and part-number printed on it. If you can read that information from the old belt, a google search may provide you with multiple sources to buy on-line.
  14. Rockhopper


    APT-II sells several products (http://www.apt2products.com/) Not sure they're all truly unique from each other, as at-least two of them have nearly identical descriptions. It's described as an 'acrylic emulsion'... and, in this situation, would be considered a bonding agent that is supposed to help the wet 'over-glaze' stick better to the already fired surface. I've never used it with glaze, but I'd say if the 'Envisions' is sticking without it, there's no point in scraping it off just to re-apply with the additive. If it's not sticking, add some APT and see if it helps - but don't add it to the entire container - put a small amount of your Envisions in a cup and add a drop or two of the APT. That way you're not altering the entire container of Envisions if it winds up not working. Either way, you'll need to be extra careful handling the piece after it dries, especially when loading the kiln. Even with the APT, the added glaze will definitely be more susceptible to being scratched/chipped off if it gets bumped against a shelf or another pot. Also: Preeta mentioned that the Envisions will look different over another glaze than it does directly on the clay (looks like all of the samples on their website are on a white clay body). You should also be aware that the second firing may also cause color changes in the already-fired Courtyard glaze.
  15. Sunshine & fresh air are probably your best option. If you're going to try vinegar - start slow, and test on one or two first before you do the whole batch.. It might be acidic enough to damage the plaster. (Plaster walls usually have paint on the by the time you want/need to clean them - so you're putting vinegar on the paint, not on the plaster itself) You might also want to try a product called Zorbex. I've never used it on plaster - but it worked well on wood furniture that came from the home of a smoker. No matter what you use, don't be surprised if the odor returns the first time you actually use the molds, as the water from your slip works its way through the plaster and re-moistens the smoke residue.

Important Information

By using this site, you agree to our Terms of Use.