neilestrick

A ball point pen works well, too.

The glass has a very different COE (coefficient of expansion- different shrinkage) than the clay and glaze, and it most likely put a ton of stress on the coasters and blew them apart. To get the piece off the bottom, try sliding a pallet knife/scraper under the chunk. You may lose a little bit of the floor but that won't hurt anything. If it has melted into the floor a bit, put a thick layer of kiln wash on it for the next few firings until it stops melting.

In addition to the potential band issue, if the outer dimensions are not the same then your control boxes are not going to line up properly. I also think it's going to affect how the kiln heats. If you had zone control it wouldn't be an issue, but with just one thermocouple the 2 1/2" section is likely to run colder than the 3" section. Plus the overall energy savings would be minimal since the lid and floor would still be 2 1/2" brick. What does it say on the serial plate for the max temp rating of the kiln? If I remember correctly, the 181 is only rated to about cone 5/6, which is the biggest reason it's struggling to reach cone 6. You're maxing it out, and you're not going to get very many firings before it won't reach cone 6 at all, like maybe only 30 firings.

There's a lot of leeway in these lid braces. If you're a few inches either way it's not going to matter.

If your white slip is a porcelain body then it might be somewhat translucent, so a thicker layer is needed to make it more opaque. Plus the iron in the dark clay is pretty powerful stuff and will tend to darken just about anything put on top of it that's not very opaque.

The slip has not moved. The color of the brown clay is coming through the slip where it is thin. You need more coats of slip.

Those dangling elements should be replaced, otherwise they're going to contact the work in the kiln and cause problems. You'll also have to replace those broken bricks or else the elements are just going to flop out again. Neither is super difficult, but if you've never done it before it'll take some time. You'll spend $65 per element and about $17 per brick to fix it. HERE is a video that shows how to replace bricks. HERE is a video showing how to replace elements. I would pass on that kiln if you don't have experience with repairs. If I remember correctly, the 231 has the old style control boxes with the early generation Kiln Sitter, which is not ideal, and not easy to work in.

I would try a cone 5 firing, on medium or med-fast. Slow is not necessary. Your glaze is probably over-fired, however bisque firing cone 04 might help.

The simplest and most affordable way to fire is with an electric kiln. They are easy to use, easy to set up, can be installed in basements and garages and studios. They don't take up much room and are easy to vent. Firing to cone 5/6 you'll have durable, vitrified pots for food use, and there are hundreds and hundreds of commercially available glazes. What type of kilns are used at your studio?

@mandyk The arm piece attaches to the lid directly above the prop, so that the arm hangs straight down in the prop frame when the lid is closed. Both attach to the left side of the kiln as you look at it, 90 degrees from the center of the hinge. THIS VIDEO shows the placement. Also THIS.

The wiring should be rated the same as the breaker.

@cadenrank When looking at a wire ampacity chart, it's safest to use the largest wire size number for that amperage, regardless of which type wire you use, which means that for 50 amps you need 6 gauge wire. Always better to over-build. (Edited for better wording)

Something is different than before, you need to figure out what. Is it the same bead rack, same wire, etc? How big is your kiln? Could the dust be from your thermocouple?

Can you describe the debris? If it's white chunks in your glaze, it's either kiln wash flaking onto your pots, or bricks flaking. Does it only happen on the top shelf? Is there any wash on the bottoms of your shelves? You can't really stop cobalt from fuming. You might try putting more space between the top of your plates and the bottom of the shelf above them. I've never heard of it fuming the bottom of a shelf, so I think it's just too close.

If it's a round kiln then it most likely does not have any of the dangerous stuff, as they are pretty simple construction- bricks cut at an angle with a steel band holding them together. There are some models that use some fiber insulation behind the bricks but those are uncommon in round kilns and easy to spot. If it's a square/rectangular kiln, then it most likely does have insulation of some sort behind the bricks. In a kiln that old it could be something harmless or something dangerous. In those cases just keep everything together and if the bricks ever need replacing, don't do it. Post some pics. Sounds like it may not have a Kiln Sitter shutoff device.

If it has all the original wiring, maybe not. There's a good chance the wire insulation is pretty crispy and brittle. Give it a good inspection and see if the wires are still soft and pliable. If they're crispy and crunchy when you bend them, I'd replace the wiring. Power cord included.

That form is going to sag no matter how it's made. You either need to fire it low enough that the clay doesn't soften up, so at least a few cones lower than its maturation point, or you need to support the middle dips. You could just do a couple of little dimes sized unglazed spots on the bottoms of the dips where you could put a bit of clay to support it in the firing. If it's the same clay as you made the piece with then it's going to shrink with the piece.

If you over-deflocculate it goes the other way. Kinda like chocolate seizing. Been there many times...

When you reduce an iron bearing clay body, the iron goes from red to black, and then the surface reoxidizes during cooling. If you cool in reduction, then the iron stays black. You need a clay body with 4-4.5% iron if you want black. To do it well, you need to be able to seal off the kiln but still be able to introduce a small amount of reduction. In a wood burning kiln, that means sealing up all the air holes with clay, and tossing in just a couple small scraps of wood every 10-20 minutes as it cools, down to a temp where it won't reoxidize. Very slow and boring process. In a gas kiln you seal off the burner ports but leave a small pilot flame burning for the reduction. Introducing small amounts of air can result in bright flashes of color on the surface. The first photo below is a teapot by John Neely, who pioneered reduction cooling in the US at Utah State University. It's not black clay, it's reduction cooled brown clay. The second is a piece by Susan Harris of Southern Utah University. Susan is a master of getting bright flashing in her reduction cooling pieces.

The newest design of the eFL series ships the kiln body sitting directly on a pallet. It can be unloaded with a pallet jack, however you'll need a high lift pallet jack for assembly. You assemble the stand, lift up the kiln with the high lift jack, connect the stand, and set it all down. It's pretty simple, just takes a little time to get everything together.

I use Speedball pink at cone 6 all the time. I don't love the color, though- too salmon for me- so I cut it 50/50 with white to get a nice soft pink. Could be your clear glaze causing the burnout, or maybe not putting the pink on thick enough.

What brand and model of kiln do you have? It sounds like a Duncan? If so, use the search bar at the top of the page to search Duncan and you'll find some very good threads talking about how to fire those kilns. They're a bit of an oddball in the kiln world, but folks have figured out which settings work best.

That mix is a beautiful color, and if you have a pugmill then making the blend would be pretty easy, although still a time commitment. Also easy enough to have the manufacturer make it for you. The workability would probably be really nice, too. Despite saying that Hansen's body is expensive, I really go back and forth a lot on my opinion on clay prices. On one hand it's a major layout of cash to buy 2000 pounds of a body that costs $2 per pound, but on the other hand, compared to the 88 cents per pound that I'm paying now for a good porcelain, the price could easily be made up by raising prices just a little bit. The cost per pot is still very low in the big picture, but having that much money tied up in inventory would be horrible. You can make up a little bit of the cost in lower firing costs and longer element life, but nowhere near all of it. There's not going to be a financial benefit to $2 per pound clay. The red cone 1 blend would definitely come out ahead, though. Same price as what you're using now, lower firing costs. I imagine a cone 1 porcelain frit body could probably be made at a similar price to a cone 6 porcelain, since it wouldn't take as much frit at cone 1 and the neph sye would come into play more. I might have to take some of my porcelain and try some frit additions to see what happens.

I looked at that, and was wondering why 03 with him, too. Hansen's recipe is crazy expensive even if you use grolleg.

It's also really easy to over-reduce when reduction cooling, and can mess things up. It really takes very little fuel if the kiln is sealed up halfway well.