fergusonjeff

Since you are not too far away, here are a couple options. About 10 years ago I convinced Alsey (a hard brick manufacturer in Illinois) to sell me three pallets of "seconds" for a significantly reduced price. When they arrived they looked perfect to me and have done well in my wood kiln. These were super duty bricks. I think they were not really seconds and they were just being nice. They normally crush up any rejects as grog in future batches. https://www.alsey.com/ One other option: There was a second-hand refractory store near St. Louis that closed a few years ago. A local guy that makes an occasional pizza oven bought all the remaining inventory he could move. I bought a large load of 4x3x9" really nice bricks for only around $1/brick just a few months ago. He probably still has a large inventory, particularly of large and odd-shaped bricks. I can try to contact him if you are interested. Would be a bit of a drive though.

The sharing that goes on here is even more valuable than I had realized. I am the lucky pottery who met up with Mark in St. Louis a week ago. I knew I had absorbed a lot of his tricks of the trade from this site, but I did not fully realize how much. As we talked for an hour or two in my booth, almost every aspect of my pottery has some mark of his influence. From the way I wax my pots to the design of my display shelves - Mark's influence and generosity are everywhere. Helpful potters like Mark and Neil E. deserve a lot more credit than they get.

Not all rock chicken grit is feldspar. I got some from another potter that worked, but all the chicken grit (rock kind, not shell) I can find now is granite. Can add interesting texture but does not melt even up to cone 12.

I only use soy wax. Less toxic than paraffin, but still smells when burning off in the kiln. I buy a bulk 10 pound bag from Amazon every few years, Just keep it in a sealed container. Mice seem to like it.

Finn, As an archaeology professor who does lots of experimental work , I am curious to know more about your project. What are you planning to do? I would be happy to try to produce the pieces for you, but shipping to the UK would be prohibitive. An old knapper friend of mine delivered concrete to the Coors (yes the beer company) plant. I guess during prohibition the company started producing specialized ceramics. He would go through the massive waster piles and get some interesting knapable pieces. Worked like a slightly grainy chert. Only real problem was it would produce a very loud ring when flaked that would require hearing protection. I am not sure if standard cone-10 porcelain would have the same density as the stuff Coors makes. .

The dip in pressure you are getting is the vacuum finally getting to the mixing chamber. When the mixing chamber is full and you are mixing mode, there is a seal of clay that forms between the back chamber (where the vacuum port is) and the mixing chamber. When you start pugging it allows a small gap to form along the mixing shaft that then removes the air from the mixing chamber. This is more pronounced if the mixing chamber is overstuffed. After getting the vacuum established in the rear chamber using mixing mode, I switch to pugging mode and slow speed. Usually where there is about 4-8 inches of clay out of the nozzle the seal will break that releases the vacuum into the mixing chamber. Keep slowly pugging until the gauge shows the vacuum back up. then reverse direction to mixing and allow the extruded clay to be sucked back into the chamber (be sure to replace the cap). After a few second of mixing, then return to pugging and extrude the full batch. Usually, the first 6-8" has some minor bubbles so that just goes back in the next batch (or I keep that aside for handles and other attachments).

Peter, I may be reading it wrong, but I think the original poster was referring to using bone and shell as wadding rather than as posts. Shells work great for wadding during the firing, but within a few days turn to powder. I imagine bone would be similar, but maybe less structurally stable during the firing. Jeff

Excellent question, and I am looking forward to responses. I think it depends on the temp you are firing to. My understanding is the granular manganese is better at cone 6 (melts and of-gasses too much at cone 10) and granular illmenite (or magnetite) work better at cone 10.

Thanks for the advice on the copper reds. Fired again yesterday and went with heavier reduction. Still too hot to open early this morning, but a quick peek showed some nice red test tiles. More reduction and thicker glaze seemed to help.

Neil - the copper reds were going green where thick. So I think I need both heavier reduction and thicker application. I ended up going past cone 11 throughout the firing. Would the higher temp cause issues for the reds? Mark - Let me know when you are ready to pass on your old 12x24 advancers. Definitely in the market when you are ready.

Mark, thanks for the info. Just peeked into the kiln this morning and the shelves looked fine. Still too hot to unload. This is my second time firing a gas kiln (used to wood and electric) and based on the quick peek at the copper red samples I am still not getting enough reduction. Hopefully I can get that worked out. I am definitely interested in the shelves. I would like to get about a dozen at least. If the price is right then shipping in small batches or meeting up somewhere would be great. Jeff

Mark - Question on the quick cooling. I have a new (to me) 14 cu ft olympic gas kiln. I have only fired it once before and have it loaded to fire this weekend. I have two new bailey shelves in the stack to try them out (I really like the advancers in my electric kiln). The kiln cools fast on its own (can open the next day). I am not opening anything to purposely crash cool but it is a fiber-lined softbrick kiln that just cools quickly on its own. Would this pose any danger to the shelves? I have them in the middle of the stack right now but plan to keep adding more over time. Thanks.

Just a little additional clarification, LiDAR works by continuous scanning from all angels and would require more than a single shot. The background would not really matter because it is not using the visual image but laser detected distances in a large point cloud. You would then have a large data file to export to some processing program. Might be a lot easier to just have a series of boxes and the smallest one it fits in is a specific price.

I also get my Tin from them and it has always been fine.

For my main 3 glazes I got big 20-30 gallon tubs from the farm supply store. Have held up well for over 5 years. got cheap furniture dollys from Harbor Freight and just added slightly larger wood tops. made covers from plywood. I have used square 4-5 gallon icing buckets for all other glazes. The square shape is better for dipping most items than round buckets. Get them free from Sams Club.

Thanks Neil. That is what I was afraid of. I have been really happy with my 26" half round advancers at cone 6 electric. Just hoping there was a better solution than $5000 all at once.

I am currently mostly firing a wood kiln and use 12x24" silicon carbide shelves that have held up well through about 30 firings. I am planning to build a gas (cone 10) kiln that will use the same size shelves. I would like to start buying 12x24 advancers, but at almost $300 each that is too much at one time. I plan to fire lots of flat plates and flat shelves are critical. I know there was some discussion of the nitrile bonded shelves with the cuts, but I don't remember if they are reasonable substitutes for advancers. Here is a link to some that are only $100 per shelf. https://nmclay.com/lgrf330-shelf-sil-carb-nitride-bonded12x24x-394 Any thoughts? Thanks, Jeff

I think uneven heating is the issue, which is why I don't use them in my wood kiln. I have a few 26" half-rounds that I use in my electric kiln up to cone 6, and use the fast glaze fire setting all the time. No problems. The advancers solved all my warped plate issues. I make some slab plates and bisque on edge. They warp quite a bit, but come out dead flat after the glaze fire on the advancers.

Mark, If you get stuck needing a home for more please let me know. I'd happily pay $100 each. I have looked for years and have never found any used. I did once get some seconds (never could tell what was wrong) for my electric kiln. I realized my previous post listed them at $3000 each. Obviously a typo. They are actually $270 each after shipping, but without tax. Jeff

No kidding on expensive. Building a gas kiln and need ~15 12x24 shelves. With shipping they are almost $3000 each. I am building the 20 cu.ft. for less than that.

I built the type of cross-draft kiln in Neil's drawing a few messages earlier. Works really well. Not always a lot of ash build up, but you can supplement with sprinkled ash prior to firing. Works really well for glazed wares. I can fire it in under 10 hours to well over cone 10. Just fired it yesterday and that will be my last firing until fall. Not fun to fire in the summer (heat stroke last time I tried) or the winter (10+ hours outside in the cold). I have fired it about 25 times and getting better results each time. I just fired it yesterday so waiting for it to cool to see how it went. The version I built is about 18-20 cubic feet. Anything smaller would be very difficult to fire. There are very specific plans for this published, but I am forgetting to book. If you are interested I can get the reference.

When I used my Peter Pugger 20ss for mixing dry clay I found that aiming for about 25# dry ingredients was about right for a batch. just mix your dry ingredients well and then add with water until full. It took a while to figure out how to avoid the spins, but not bad. Pug out a batch and then add in the next 25# and go again. I would usually let it sit a few days and then repug it to the specific moisture content I need.