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About Rockhopper

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    Southwest Ohio
  1. Rockhopper

    Red glaze question

    Others, with more experience & knowledge than I, may have a different response - but I would say if your work is fired to maturity (both glaze and clay), and there is no cross-contamination from other pieces in the kiln, then a food-safe glaze on a food-safe clay is going to be food-safe. However - even the "dinnerware safe" glazes you mention have disclaimers that say it's the responsibility of the user to test their finished product to be certain it's safe... (Example from one of Amaco's Potters Choice glazes: "Tableware producers must test all finished ware to establish dinnerware status, due to possible variations in firing temperature and contamination.")
  2. Rockhopper

    Blistering / What Causes it?

    I see holes spread across most of the white glaze. Looks like it's doing the same thing all over - but it's thicker at the bottom, so the bubbles don't pop - and turn into blisters instead of tiny craters.
  3. We have a set of store-bought canisters that we're replacing - so determining correct finished size is no problem. They're just a lot bigger than I'm use to throwing, so wanted to get a ball-park range of how much clay to use. I will probably start with 3-4 pounds, and see what I can get from that - then figure out how much to add, to get to the size I need for the biggest one.
  4. Thanks DM. Just watched this video a few days ago, showing it done that way. Definitely something I'm considering. Might be a few weeks before I get 'round to tackling this project, but will post results when I do.
  5. Rockhopper

    Brent CXC wheel problem with fuse?

    It looks like that small circuit-board ~could~ be removed and replaced - but check with Amaco first - and be VERY careful. The large blue capacitor could give you quite a shock, even with it unplugged, if it hasn't discharged yet and you accidentally touch both terminals (or components connected to them) at the same time.
  6. Rockhopper

    Brent CXC wheel problem with fuse?

    Make sure your fuses are "slow blow", as listed on the Amaco website. Doesn't have to be from them - just has to be that type. "Slow blow" means it's able to handle the initial surge required to start the motor spinning, but still protect against a sustained overload. A regular 'fast-blow' fuse may blow when you start it up, even if there's nothing wrong with it. As Mark's comments suggest - a popping sound usually indicates a direct short, such as from a worn, or loose wire arcing against a metal housing. Another thing that could produce a pop is a failed capacitor on the controller board or power supply. I had a computer power supply make a pop and suddenly stop working and, when I opened it up, I found a capacitor that had the top blown off of it. I've never opened the controller on my wheel, but I'm guessing there are at-least a couple of capacitors in the controller and/or power supply. The pic below shows both a normal 'cap' and one that has leaked. There are different types, and they come in different colors and sizes - one thing they have in common is that a normal one should have a flat top, like the one on the left. If you see one that looks burnt, like the one on the right, or is split open, that's definitely a problem.
  7. Rockhopper

    Best Cone 6 Porcelain?

    Is there another supplier anywhere close to you ? Sounds like this one is more interested in protecting their recipe than they are in helping their customers. (And/or they really don't know what's in it, and don't want to admit it.) Either way, I think I'd be looking to buy my supplies elsewhere if possible.
  8. If the hole is big enough, maybe a coat of clear epoxy on the inside would serve the same function as a metal sleeve - but be less visible ?
  9. Thanks Mark! I'm throwing Standard #112 stoneware... and skill level (or lack of) will definitely be a factor. I've made a few pieces the same height as the largest one I'm aiming for - but they've all been vases, about half the diameter. But.. hey, it's new-year's eve... what better time to start making plans to 'expand' my skills I just measured the large one I would be replacing ... it's approx. 6.5 - 7" across x 8" high not including the domed lid... How does that compare with your 10# size ? I'm guessing you mean cm ? Those sizes in mm, converted to inches would be (approx): 3/4" , 5/8", and 1/2". If cm, it's approx. 8", 6", and 5"
  10. I agreed to try to make a set of 3 canisters for my wife, to go with the wall tiles I'm making for the backsplash in our kitchen. The largest would need to be big enough to hold five pounds of flour. Most of my throwing has been mugs, bowls, and a few relatively small vases - nothing over about three pounds starting weight. I know I would need more than that, but have no real idea how much more. I realize there are a number of factors that could influence the answer, but would appreciate suggestions for a good starting point.
  11. Rockhopper

    Prediction required

    Just re-read OP a little closer, and looks like you already figured out where you went wrong... so, being one who likes a math challenge, I dropped your numbers into a spreadsheet, ran some calculations, and it looks like in order to restore original recipe percentages, you would need to increase your batch total to 8000g (for round-numbers). The 'inverse %' column divides your qty used by the target percentage - to figure out what the total qty would have to be in order for the qty used to equal the desired % of total. I picked the largest number in that column, and rounded up. Then, in the 8000 column, multiplied 8000 by original percentage. Last, subtract the amount you used from the number in that column, to determine how much to add to restore target percentages. Bottom line: Unless you think you're going to use a LOT of that glaze, you might want to just toss it and start over.
  12. Rockhopper

    Prediction required

    You were doing fine until you got to the Frit and OM4. Looks like you got off track after getting 'called away', and multiplied your running total by ten, instead of the original item quantity on these two ... Frit 3134 6.8 x 10 = 68 (vs 53.4 x 10 = 534) OM4 23.3 x 10 = 233.
  13. I've searched the forums, and found some threads discussing "at what temperature can I open my kiln" - but all that I've looked at are focused on internal temperature of the kiln, and how cool does it have to be before you open it. My question is in a slightly different context: What is the maximum recommend differential between internal kiln temp, and ambient (room) temperature when opening ? My kiln is in an unheated garage, that currently has a "room temperature" of around 30*F. I know if I start unloading too soon, I'm risking problems from thermal shock. Obviously, I could just open the lid & see what happens - but I get plenty of chances to learn from my own mistakes (like plates that split when I dried them too fast) - so I try to learn from mistakes made by others whenever possible. ;-)
  14. Rockhopper

    Frankenkiln help

    Just curious... did you wind up getting Sparky to check out your wiring, and did it pass ? Reason for asking: I'm pretty sure 6/2 NM ("Romex") wire is only rated for 55 amps max. I don't think I've ever seen a 55-amp breaker, so maybe they allow the 60. I'm not an electrician, and it's been a while since I looked at a code-book, but when I was managing the electrical dept at a local home center, both the wire supplier and the breaker manufacturers told us allowable breaker sizes for 'Romex' are 14ga=15amp, 12ga=20amp, 10ga=30amp, 8ga=40amp & 6ga=50amp. Mostly bringing this up because - since you don't own the property - if you didn't have it inspected, and something goes wrong, you could wind up being held liable for any damage to the property if it wasn't done 100% according to code. (Even if the land-lady is OK with it, her insurance company would likely say otherwise.)
  15. Rockhopper

    Why did my plates split ?

    Leaves were applied before trimming - probably "cheddar cheese hard". When I'm putting them on mugs, I trim first, and apply the leaves after I attach the handle - then wait 'til it's completely dry before I pull them off. Since they covered a significant portion of the plate, and the rim was already drying much faster than the rest, I peeled them off after trimming.

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