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fergusonjeff

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Everything posted by fergusonjeff

  1. Not sure the reconditioned list on the peter pugger website is worthwhile. For example one listed there today had already sold long before I checked on it about 5 years ago. Finding a used Peter Pugger is next to impossible.
  2. The "spins" is well described in the above two posts. sometimes even adding it slowly on the left as Mark suggests is not enough. It can help to get the chamber really full and then close the lid but don't lock it. The clay will slowly push the lid open and then you can restart the mixing. the pug-mill is a vastly underrated tool. It was a real pain when I would have to try to add water to clay bags and then let them sit for a month or so to even out the moisture, You are then stuck working with whatever stiffness you have for whatever you want to throw. Then you either throw out your scrap or spend a lot of time and space reclaiming. It can improve your work in other ways too. It is nice to know that is something does not turn out the way you want, you can just throw the clay back into the next batch.
  3. I have the 20ss model and it has been the best pottery purchase I have made. I mix different commercial clays and switch out between cone 10 (wood fired) and cone 6 every few months. I can adjust the mixture for the day's throwing according to how soft I want it and the consistent 3" pug allows me to cut regular sizes easily for repeated throwing. I add in whatever scrap (does not matter if wet, dry, or anywhere in between) and usually let that sit in the mixer overnight just to even things out. I have mixed some clays from scratch, but it is very finicky and i generally avoid it. There are better ways to mix from scratch. There is a slight learning curve, especially when adding water to avoid the spins.
  4. Bill, That is helpful. I'll be doing my last wood firing of the spring in a couple weeks and will limp by with my fiberboards, but that gives me all summer to find some shelves before the fall firings. I am pretty sure they were not referring to core-lite or the nitrile bonded stuff, just newer (according to them, non-mullite) shelves. The thought was no one made "mullite" shelves any more and the newer shelves cannot handle the temperature differential of a damper in a wood kiln.
  5. I was told "new" shelves don't work like the old ones and will crack as dampers. That is why I was trying all kinds of other options. Would something like this work? https://www.sheffield-pottery.com/KILN-SHELF-p/spha08.htm
  6. Mark, I tried to find mullite shelves for dampers but was not able to . Not sure they are made any more. Do you know anywhere I could get them? The fiber boards mostly hold up, but warp a lot. I am on my 6th firing with the first set. They hold up better than my previous attempt which was 1/2 thick steel plates.
  7. Thiamant, A cheap grinder is fine. I have about 5 and most were under $20. The wheel you show is for cutting bricks, not grinding surfaces. Look for one more like this: https://www.ediamondtools.com/products/premium-turbo-diamond-cup-wheels?variant=11941428932&gclid=CjwKCAjw9MuCBhBUEiwAbDZ-7qLxkyvo0l-3rMlytTa0pH5Vy9oOgZCtsJfOoLImBx47F3tZP_-VlhoC4SMQAvD_BwE
  8. I second the diamond cup wheel. They are much more expensive than a masonry disk, but will remove glaze that masonry disks just seem to heat up. I found a diamond cup wheel at harbor freight for under $30 and eventually replaced it with another cheap one from menards.
  9. The push from underneath just goes through the lid into the knob, but not all the way through.
  10. I used to have this problem on small knobs of clay I would add to lids (at leather hard) and carefully throw. The lid and knob are at too different stages of drying. Another potter showed me a simple trick once that has worked every time. I take the blunt end of a needle tool (1/4" round) and push up through the lid into the newly added handle. I don't mind the small hole on the inside of the lid and have not had a single handle/knob detach since.
  11. This is the same clay I use for most of my cone 6 work. I usually mix it about 50/50 with other cone 6 porcelain or stoneware. Laguna makes another speckled clay you might try, but it is sometimes harder to get. I thin the number is 608. I think it trows much better than 403 but if anything it has even more speckle. I think 608 is more brown compared to 403 being more yellow.
  12. I agree with Neil. My standard cone 6 mix is 1/3 each of speckled stoneware, red stoneware, and porcelain. My cone 10 wood fire mix is 1/2 course stoneware (Rods Bod) and 1/2 various porcelains (some commercial, some home-made). The mixes all throw and fire better than any of the individual clays. I did have a light colored cone 5 stoneware once that bloated a lot at cone 6, even when mixed with other clays. I am still thinking the mixture was bad. Took a while to get all that bad cone 5 clay through my mixes.
  13. I am currently using fiber boards as dampers on my wood kiln. I got them along with some kind of liquid (I think a silica) that I painted on the boards heavily. After drying they are pretty strong. I have used the first set about 4 times and they do warp a little but have remained intact after 12-hour cone 11-12 firings. I would prefer to use kiln shelves but not sure any can handle the temperature differential across the shelf. I have used 1/2" thick steel plates, but these warp and degrade quickly.
  14. I use that same clay for Cone 10 wood firing. You are basically just talking about bisque temps. It is definitely not waterproof at those low temps. I doubt the low-fire glazes would fit well enough to provide any good protective layer. The speckles in Rods Bod are mainly from iron, and they take the high temperatures (like cone 10) to develop. My bisque fired rods-bod (what you are planning) is just an off-white color and very absorbent.
  15. The analysis we do just provides a compositional profile - usually about 33 elements. Determining the origin is where it gets complicated. You would need lots of known samples from potential sources and hope that the recipes are internally consistent (from the same source) and there is clear distinction between sources. Ceramics do not work like obsidian. I do a lot of work with obsidian (stone tool) sourcing as well, and in that case we can usually directly match an artifact to a specific geologic source. Clays are way more complicated. As a side project, we recently completed a detailed analysis of a bunch of commercial clays as part of creating a calibration set for X-ray flourescence analysis. We did not analyze mixed commercial clay bodies, but rather primary clays such cornwall stone, EPK, and RedArt. If anyone really wants the data I think I should be able to share it.
  16. If you are really interested in a large-scale study, and have lots of money to throw at the analysis, then you could always conduct neutron activation analysis through my lab. In reality, this would be a pretty expensive proposition, but you might like to look at the lab website just to get an idea of what a study like this could entail. My day job is as an archaeologist with a partial appointment in the lab. archaeometry.missouri.edu There are some other analytical options (such as XRF or ICP-MS), but they have generally lower precision and accuracy.
  17. I have had a SS Peter Pugger for about 5 years and used almost daily. Not a speck of rust or corrosion. I use some porcelain in my mix also. I am interested in hearing how your situation turns out.
  18. I use hardwoods (mostly oak scrap from wine barrel and pallet making) early in the firing when I am looking for a slow steady climb, but in the later stages the hardwoods just burn too slow to maintain or increase temps over about 1900 degrees. Hardwood (especially oak) ash also takes longer to melt, so switching to pine for the last few hours helps reduce crusty ash buildup on the pots. Flame length can also be an issue. Pine has a shorter burn length. I have a smaller single-chamber wood kiln, so it does not matter much, but it could be harder to heat the back of the kiln the same with soft woods compared to hard woods.
  19. MFP - I think what you are seeing as "darkening" is just the shadow of the hollow sections of the shelf. I have been using a few of these corelite shelves and they have held up well. Seem to warp less than the solid shelves at cone six. I just got a couple 1/2 round 26" advancer shelves and they are even better than I expected. Plan to order more once they get back in stock.
  20. I think Mark means to add water through the hopper (top), but at the side toward the barrel end. This is what I do, and it allows the water to mix before it works through into the vacuum chamber.
  21. I have the VMP20, but use the same strategy as Marc. Just add water a little at a time and be cautious to avoid "the spins".
  22. I have been using the SS20 daily for about 3 years now. Here are some answers to your questions. 1. Has anyone gotten HOLES in the center of their clay logs from a PP? Only at the beginning of the pugging. Not more than 5-6 inches with some air pockets. 2. Do PPs also have to pug super slow? My Baily was fast. I use a top speed when pugging. usually takes about 1-2 minutes to pug out 30-40 pounds. 3. Does a lot clay get all stuck in the lid? Does it have to be cleared all the time? There is definitely some that builds up on and around the lid, but not a problem to scrape off every once in a while. If it builds up around the seal it can dry out and create some vacuum leaks, but still easy to clean off. 4. Does water tend to get shoved up into the lid area clay, not allowing it to affect the batch? Mark and Glazenerd have addressed the water issue. Getting the "spins" is often a problem when adding water, but if added in small amounts in the front of the chamber it usually works itself out. 5. Is the issue with sucking back-in the clay for the De-Airing to reach both chambers at least a "reliable" and a repeatable task for success? With the PP, the vacuum is first created in the rear chamber. I usually need to start pugging to get the seal to pop and vacuum out the clay chamber. It usually occurs after pugging out about 5-6 inches. I then reverse the direction and pull the clay back in and mix for a few seconds. then just pug everything out at full speed. 6. Can you mix batches a little wet or a little dry to suit your needs, without major issues (not pugging, holes, bubbles, etc.) I adjust wetness to what I plan to throw. there are definitely points of too wet or too dry for it to work well, but usually those are outside the range you would want to use anyway. 7. Are single augers, though stronger and won't break down like dual augers, doomed to have these issues? Not sure. no experience with dual augers. 8. I can't spend more than $5,000 I think the SS20 will slightly exceed that budget. I tried for months to find a used one and gave up. Don't bother with the used list on the PP website. Most of the ones still listed sold many years ago.
  23. Thanks for the photos Min. I was not following the text description and assumed it was much more complicated.
  24. I use a lot of Laguna Speckled Buff (#403 I think) at cone 6. The granular manganese gives great speckles through any glaze I have used. I got really nice speckled white using this clay and Van Gilder's waxy white glaze recipe. The glaze is usually clear/tan in a uncontrolled cooling, but is a nice speckled white using a controlled cool.
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