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fergusonjeff

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About fergusonjeff

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  1. Kiln brick question

    This may end up being a great purchase. They look like standard straights (9" x 4.5" x 2.5"). $0.50 per brick is a great deal if they are high-duty or better. Chances are they are super-duty bricks or even higher. I ended up using a mix of high, super, and whatever is even higher than that in my wood kiln. The only downside to higher-temp bricks is some can be very difficult to cut. I used a circular saw with a masonry blade to cut bricks and a regular high-duty brick will cut in just a couple seconds. The really hard bricks could take minutes and eat up a lot of the masonry disk.
  2. What are you putting the mugs on after you cut them off the hump? I have had more even drying if a put them onto a large plaster bat.
  3. Mixing Pugmills

    I have started mixing clays in my small peter pugger (VPM-20) and usually make about a 35 pound batch at a time. It is not quite as simple as just throwing in the powder and water and then making the clay. If I had a mixer (like a solder) I would use it to mix and then send it through the pugger. The pug mill tends to need about 80-90% capacity for it to mix, otherwise it just spins a large ball. The same pointless spinning can occur just from water additions. It takes a while to figure out how to break the spinning and start mixing again. The larger sized peter-puggers might be much more efficient for mixing clays from dry ingredients. Mark, have you used your larger pugger for mixing clays from dry ingredients?
  4. Salt Fired Pieces In Electric Kiln

    Marcia, Thanks. I have only done it twice, so hopefully not too much damage. I plan to refire some of the better pieces in the wood kiln, so I will stop torturing the electric. Jeff
  5. I recently fired my new wood kiln for the first time. Had a few issues (now solved - I think) that caused excessive reduction throughout the firing. The pots came out with almost no flashing despite the extensive use of flashing slips. At the end of the firing we added about a pound of salt for just a little extra shine. Most piece got very minor or no salt effects. Just as a test I have been sticking a small piece or two into the center a bisque firing in my 10 cubic foot electric kiln. The color change is pretty dramatic with a strong shift to oxidized reds and oranges. I am bisque firing to around cone 05. I am also using a down-draft kiln vent throughout the firing. The attached photo (if I get it attached correctly) shows two pots that looked just like the one on the left after the wood firing. The one on the right went through the electric bisque. QUESTION: Is there likely any significant damage to the electric kiln through the introduction of a small (about 2 mugs per firing) amount of slightly salt-glazed pieces in a bisque firing? What temperature is needed to re-volatize the salt enough to possibly cause problems? Thanks, Jeff
  6. Kiln Shelf Warp Question

    Thanks Neil. They seemed too good to be true so I only bought 2. Guess it is time to get some more.
  7. Kiln Shelf Warp Question

    I use usual solid electric kiln shelves (3/4" thick 26" half-round) in my 10 cubic foot kiln typically fired to cone 6. Using three stilts puts the long diameter side with only supports at the ends. They warp almost 1/2" within about 10-12 firings. I then remove the wash, flip, and re-wash. They do flatten back out, but only temporarily on their way to warping the other direction. No cracking from this yet. I recently purchased a couple of the hollow (core-light?) shelves and they have gone almost 10 firing and no warp at all. They are not much more that the solid shelves. Might have to start slowly replace all the solid shelves.
  8. Purchasing any major equipment is a decision unique to each potter. I bought my pug mill for a couple anticipated uses (including recycling scrap) and have found it far more useful that I expected. As Mea noted, it is a great tool for adjusting the softness of clay. I throw some items with soft clay (plates and flower pots) and other with stiffer clay (tall forms and mugs). I just pug a batch (around 35#) for whatever I am planning to throw. The consistent diameter pugs are also very easy to cut into regular lengths to save weighing clay for repetitive forms. Here are some of the other uses for which the pug mill is a great help: 1) Adding things to commercial clays. I was getting a lot of minor warping on my cone 6 commercial bodies, even firing at a good cone 6. I regularly add a couple pounds of fireclay and a couple pounds of sand to each pug mill load and that has perfectly fixed the problem. 2) Mixing clays. I really like the speckling of a commercial Laguna clay, but there is more than I need. I have lots of porcelain, brown and red clays that all play well together. I use at least half the speckled clay and then just add whatever else I feel like. 3) I am now also producing a lot of pots for cone 10 wood firing. It only takes a few minutes to scrape out the pug mill and then I can switch back and forth (about every month) between the regular cone 6 production and cone 10 clays. There are not many commercial clays that do what I want for wood firing, and they can get fairly expensive. I can make my own from powdered ingredients for considerably less (depending on the recipe) and I can make whatever modifications I want. I usually just pug out a load for that day's work and then throw the next day's dry mix and water into the mill. I mix it for a while and then let it sit overnight. The next day it starts all over again. There is definitely something satisfying about mixing your own clay body. 4) Although I don't do this, there is also the potential to use the pug mill as an extruder. Deciding on such a large investment should not be taken lightly. I could not be much happier with my decision, but it would not work for everyone. The nice thing about a good pug mill is that even if it did not work out for you, the resale is very high. I purchased mine at a time where the tax write-off was very helpful. I would definitely think hard about racking up a lot of debt to purchase one.
  9. Peter Pugger posts reconditioned pugmills on their website, but just be aware that it is not regularly updated. I called about one over a year and a half ago (before I ended up buying new) and it had sold 6 months before. I let The company know, but I just checked and it is still listed - 2 years after it was sold. These are really hard to find used. They took my offer of a few hundred off list price and I sent a check. If you are looking for the VPM-20, it is pretty easy to build a heavy-duty rolling table better and cheaper than the one they sell.
  10. Peterpugger Mixers

    I mix a wide rage of stiffness from really soft for throwing plates to pretty stiff for tall vessels and slabs. I need to use the same process to break the vacuum seal regardless of consistency.
  11. Peterpugger Mixers

    Claudia, I had some of the same issues with mine (same machine you have) initially and there are a couple tricks that work well for me. 1) Fill the chamber and mix as long as necessary. I often mix very different clays (porcelain in with very dark clays) and find it mixes pretty well in just a couple minutes. The only time I let it run 10-20 minutes is when I am adding large dry scrap that takes longer to integrate. The first few inches to pug out does not mix well because it is generally clay that was stuck in the end that does not get integrated into the mixture. 2) Start up the vacuum while mixing. Stop mixing. At this point you are probably only getting a vacuum in the smaller back chamber. Switch to pug and turn the speed all the way down. start pugging. Usually about when the pug is 2-4 inches out the end the vacuum seal (caused by the clay) will break and enter the main chamber - this is when the vacuum reading will drop. I usually stop the machine for a few second and let the vacuum catch up. Now switch back to mix and let the pug get mostly pulled back into the machine. Put the cover back on the end and let it mix for 10-30 seconds. Now switch back to pug and pug out at whatever speed you like. You are really just trying to break the clay seal that is formed along the shaft that allow the vacuum to get between the first and the main chamber. the first 5-10 inches is usually not well mixed and sometimes has small bubbles because this is the clay in the end of the machine that does not get mixed well (see next hint to help reduce this amount). The first few inches usually does not have a very smooth exterior, but I don't worry about this. 3) One more trick - When I am done pugging out everything in there I switch back to mix before releasing the vacuum. This allows the machine to pull a lot of clay back into the main chamber and reduced the amount left in the end. There is often a dramatic pop and hiss when the vacuum breaks on the clay in the end of the nozzle. 4) In cases of doing a lot of mixing, I would mix the clay for a few minutes, pug quickly (not worried about getting all the air out as described in #2 above), and then throw it back in for a second round. Every couple months I am switching between cone 6 and cone 10 clays. I clean out as much as possible before the switch and then run the first batch through a couple times to get a thorough mixture. Hopefully this all mikes sense. There is a you-tube video of a peter pugger that showed about breaking the vacuum seal into the main chamber. It is 10:00 in on this video: https://www.youtube.com/watch?v=gmADuePrHiI
  12. What Type Of Sand? To Add To Clay.

    There has to be something similar in your area. I think it's main use is in some kind of water filtration application. Maybe my area is unique in using some strange water filtration method. I have seen it though the local clay suppliers (Missouri) but it is more expensive. For example, through the KC pottery supply place I use it is $17 for a 50# bag compared to $5 from Menards. I just looked on a NH Home depot page and it does say not available. I wonder if you asked directly if they could bring some in. I am curious what the main use of this sand is, and why it is only regionally available. All the home stores around here (HD, lowes, and menards) have some version of it on hand in large quantities all the time.
  13. What Type Of Sand? To Add To Clay.

    I am not sure if I can post a link or not, but I will try. It might be easier to find as "industrial quartz". Here is the silica sand I find on Home depot's web site. The stuff I have bought is the same, but in 75 pound bags. Menards has the same thing in a 20-50 mesh size in a 50 pound bag. http://www.homedepot.com/p/100-lb-Silica-Sand-520-100-4095/202080636 https://www.menards.com/main/building-materials/concrete-cement-masonry/bagged-concrete-cement-mortar/handy-sand/p-1444446377319-c-5648.htm?tid=-7072525121588110161
  14. What Type Of Sand? To Add To Clay.

    I use white silica sand from local home improvement stores (Lowes, Home Depot, Menards). It is sold near the cement, but I think it is also used a filter in some water treatments. It runs about $5 for 50 pound bags. I add a few pounds of sand and a few pounds of fireclay to every pugmill load (~35 pounds) of cone 6 clay to reduce warping. Has made a big difference. The silica sand is usually a 20-50 mesh size. I used the same sand in the mortar mix for a wood-fire kiln. Playground sand would make me a little worried since it can vary a lot more.
  15. Kiln Vent Question

    My results are not much different with the vent. It might speed cooling if you leave it on and that might cause problems.
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