Catatonic

JohnS--its been a long time responding to this (oh my, has it already been four months??? I'm so sorry!) but I have finally (just now!) gotten a call from the guy who worked on my old Duncan (Peter Yang). Here's the weird situation with that... when I first used that kiln, the dial would click at each of the firing settings--once at 7 o' clock for Overglaze, once at 4 o' clock for Ceramic, once at 2 o' clock for Hi Fire and once at 12 o' clock for Off. It all lined up with the labels on the face of the kiln. But on the very day my elements went crazy, so did the dial: it no longer clicked at the Off position, but it would click at 11 o'clock, and at 10 o' clock and at 2 o'clock. Totally mysterious. When Peter did his test firings on the kiln to isolate why the new elements he put in weren't firing to temperature, he just dealt with it as it was--didn't worry about the clicks, but just used the arrow as his guide because it was installed correctly with the flat bit facing Off. So that's the end of the story, I guess. He tells me that the original Duncan dial was installed right side up, but the later dials made by Paragon for the old Duncan kilns were to be installed upside down. The newest dials, apparently, are completely different and require a conversion kit. I don't know if this is any help at all, but there you have it. Cat

Bill— It’s not a matter of turning it in the right direction, it was more a matter of the mechanism behind the knob not acting as it did prior to that last firing. All of a sudden where before it had a natural stopping point at each one of those settings, it no longer did; in fact it would actually click in areas that didn’t have a marked label on the face. It seemed that it was out of sync with where the settings were supposed to be. I couldn’t really tell where “on” really was.

Apparently you are just as technical as me, and another cock-eyed optimist to boot! ;0) I think psychologists call this behavior, "equity rescuing". I just checked and yes, the arrow should be in line with the flat part of the --ahem-- thingy. That being said, I will mention that this dial was part of the drama I mentioned above. In the first several firings, the arrow coincided with the labels on the face of the control panel, and I got a satisfying click at the Off, Overglaze, Ceramic and Hi Fire positions. Somehow during the firing when the elements first went bad, it went wonky and has remained so ever since (somehow my kiln guy could make it work but I have no idea how. I will contact him to ask and get back to you on that if you like.) Now it clicks when the arrow is at the 10 o'clock position, the Hi Fire position and Off. So I'm missing a click, and there's no way to settle if the works behind the dial have offset by some regular interval, such that I could just relabel the dial. And now that I have rewired for the new kiln (different power load) I can't plug it in to test at what setting the elements actually turn on, so sorry, friend. Maybe it needs some new dial works ....thingies... Oops, there go the brakes.... =^x^=

John, here's what I did on my last successful bisque firing, using Bill's recommendation of reimagining the dial. I used "clock settings" though. I started at 10 o' clock and sat there for two hours, increased to 8:30 for an hour and 50 minutes, then to 7 o' clock for an hour and 10 minutes, then moved to "Overglaze" setting for two hours, then to "Ceramic". It shut off after an additional 2 hours and 40 minutes. Everything seemed to come out nicely and gave me around a 9.5 hour burn. After this I invested in a pyrometer so I could dial things in more scientifically. Now for the rest of the story. I did a total of 5 bisque firings with that kiln, and in the last one a couple of elements failed. Barely made it to temp and took ages to get there. So I priced out new elements, which I posted about on another thread. Found a supplier in MI that would make some for about half the price (Not Euclids, regretably). Paid to have them installed because I am not that person. ;0) Did a break in firing, which took quite a bit longer than expected, but I was experimenting with the firing schedule, using my shiny new pyrometer to see if I could replicate a "preheat" phase like you can do with a digital controller, so I wrote it off to user error. (Call me the Queen of Overthink.) Next I did a glaze load--my very first! The kiln barely got to cone 04 after 19 hours; I had to shut it off manually. My repairman did some troubleshooting --replacing every. single. part. to determine where the problem was. He did a tweak that improved the firing, but still only got to cone 04. Turned out the elements weren't made to spec--supplier used the wrong gauge wire and too many wraps, ergo, high resistance and low firing temperature. A bit of back and forth between supplier and repairman before this was admitted. Still waiting on the replacement elements, but they did offer store credit for my trouble (after I asked). During that one and only glaze firing I also noticed the fiber lid began to flake and dust onto my glazeware. Began to feel like the person who buys a "bargain car" that always needs repairs and thinks, "once I take care of the radiator, it will be reliable" but then the brakes go out. After all this my husband made me an offer I could not refuse: just buy a new kiln, get what you want, and be done (he'd just gotten a substantial raise). So I got an L&L Easy fire kiln, adding 50% to my capacity, and got a digital controller to boot. In the meantime, I did find a rigidizer to treat the kiln lid, so I will sell it, with the replacement elements when they come, to any taker willing to install them on his/her own. After all, it's been fully refurbished after this drama, and has 4 full shelves and a half shelf, all new, a pyrometer with thermocouple already installed, and the lid and floor just treated to harden it. Hopefully I can recoup some of what I put into it. So there ya have it. My joy is in my new kiln. Best of luck to you with yours. This would have been a much better story over a pint in some dusty pub, but best I can do via distance!

I guess using this stuff is something I am likely to be doing as regular kiln maintenance? Do you find it necessary to use this on firebrick parts of kilns as well as the fiber parts? Just curious.

Great suggestion! I immediately pulled up a lot of hits and found that Paragon makes one specifically for kilns for just under $14 a pint. This is a lifesaver--thanks!

The notes on this say its a deflocculant for making slip; I guess the use as a rigidizer is insider knowledge! Am I supposed to use it as is, or am I supposed to mix it with water, and if so, what proportions? Same directions as stated for making slip?

Any idea where I could find this stuff? It could at least make the kiln usable for low fire or glass work.

Better to keep it here. John S won't get much help from me!

Hi Peeps. I have a Duncan EA-820 that I just replaced the elements on, only to have the lid begin flaking and dusting all my glaze work; the kiln also misfired. Had to shut it off after 18 hours trying to reach ^6 when it leveled off below ^04. So. Much. Fun. I am wondering if the lid could be the cause of the kiln not reaching target temperature after just replacing the elements, or whether my kiln repair guy is correct in saying the elements are not up to spec. They were custom made by a reputable pottery supply place at half the cost of Paragon Kiln Company's parts, and came as coils which needed to be stretched before installation. They were broken in with a ^04 bisque firing before attempting that glaze firing. My kiln guy has been troubleshooting and all the parts other than elements, including sitter, switches, relays and the lot were tested out as a control to eliminate the chance they might be the problem. As of last two firings, it successfully reached ^04 but no higher. I could sell it as a low fire kiln to recoup some costs in good conscience and put it toward a shiny new L&L kiln if not for that flaky lid. I saw an archived thread that dealt with the question of ceramic fiber kiln lids and floors, and the suggestion to replace them with firebrick. How could that be done? And would it even be worth the cost and labor? Would love to hear some thoughts about this. Cat

Quote is actually a quote of Bill Klieb, so Bill, can you answer my question? If your bisque firing lasted only 7 hours (two hours on low, say, 3:00 position, two hours on "Overglaze" which is about 5:30, and the rest--4 hours--on "Ceramic" which is 2:30) should I bisque again? Still figuring out how to create a good bisque program that burns the organics out. This morning I'm trying a new "program" (I am the program--wake up, kid, time to turn the dial again...) Started at 10:00 position and moved up to 8:00 two hours later, then two hours later to 7:30 in order to create a slow rise in temperature. An hour later moved to "Overglaze" (5:30) where we'll sit for another hour and a half before ramping up to Ceramic (2:30). Hoping to get a nice long burn at the 200 degree rise per hour you recommended. Probably time to invest in a pyrometer so I know what its really doing, huh?

JohnS--what a pain--I hope its a simple fix! I did visit Skye--rode a bike from Glencoe (worked at the Clachaig Inn at the time) up to Fort William, caught a ferry and biked around the island and you're right--not much rain. Made the mistake of attending an INDOOR piping competition and had my ears blown right out! But mostly I enjoyed the hills and the coastline--high cliffs and lots of basalt. Gorgeous.

John S--I've had the same problem with the manual you have--it tells you something quite different from what actual, experienced potters are saying about firing. That's why I'm hanging out with the pros on this thread! (Sorry guys, but it's much more time efficient picking brains here than reading the manual! And thanks for being willing to share your knowledge!) Yes, I've concluded my kiln is a starter. When I either become more wealthy or my kids move out (don't those conditions often coincide???) I'll consider investing in an automatic. Cheers to you in Scotland. Spent 6 months there in 1986 and loved it, rain and all. What island are you on?

K S--I think I may try your firing schedule--this is my third attempt at a bisque firing with my Teacher Plus and each time the sitter drops much earlier than I expect and I'm left wondering if all the organics have burned off. First was an empty kiln, second had only a few pots and a single setting (about 3:00) and those two firings lasted only 4-5 hours. This time I used the schedule Smokey 2 posted above (one hour at 9:00, two hours at 5:30 (which my kiln has marked as Overglaze) and then the rest at 3:00, which my kiln labels Ceramic. It shut off after 7 hours total. My model doesn't have a toggle and has only one dial. I want to get this dialed in before I start messing with glazes! So I guess I need to keep playing around. My witness cones were pretty floppy on the upper shelves but nicely arched on the bottom one, so it looks like I'm getting heat pooling higher up. That kind of result is consistent between firings. Don't know how I'm going to balance things with only one control. I was particularly interested in what you called a "drop hold". Can you explain what that is, and how it works?

So, after looking closely at your photos and going through your directions, I realized the dial runs counter clockwise, but I think your written directions are intended to go clockwise (that's what 6:30 and 9:30 are meant to represent, yes?) But....do you perhaps mean 5:30 and 3:30? Just want to clarify.... thanks!

Neilestrick--I guess I should be glad mine doesn't have the 2 in 1 switch.... Now I have another question which your answer above has inspired: I have the carcass of another Duncan kiln--in its day it ran 50 amps and was a manual kiln sitter; its actually a 7 sided thing, a bit smaller than the Teaching Kiln. I inherited it free from a friend who was cleaning out her garage and only learned when she delivered it that the cone sitter and switches were gone--all it had was the switch housing (rusty) and a pretty decent power cord. (You get what you pay for, apparently!) But the bricks is pristine! I've wondered what I could do with it--is it possible to put new elements in it and wire it to a digital controller as you suggested above? The guy who repaired the Teaching kiln I now have was averse to trying that; he was afraid of liabilities or something legal like that. XD Anyway, I am interested in hearing your opinion, O noble kiln sensei!!

Unless you're like me and picking up the kilns people abandon when they upgrade to those fancy new Skutts!

If so, I am definitely in possession of contraband!

That is really helpful--thanks! As a newbie I haven't really had any idea of how a kiln like mine functions--there was no label with arrows saying, "This is how you bisque!" ;0)

Awesome! Thanks so much for helping me chase this down! Will fire it up again in a few days when a few more pots are ready, and will keep you posted. One last question. The pots I fired before-- would it be advisable to fire them again to ensure all the organics have burned off, or should I let them be? Would they perhaps get too hardened if bisqued again?

Are you talking about the dial that sets the firing cycle when you say to start with the switch off? Because there is no other switch. I've attached a photo to illustrate. If you aren't referring to the manual/automatic toggle switch that other Teacher Plus kilns have (which mine does not) then would you say its okay to change the setting in the middle of a firing cycle? ( I am half expecting you to say, "Hmmmmm....that's weird. Never seen one like THAT before!)

Guess I'd better call my kiln guy and find out if there's a way to slow it down. There are only three settings (overglaze, ceramic and Hi-Fire) and there's no apparent way to adjust the firing aside from that. Maybe I need to use the overglaze setting, which is normally meant for earthenware. In these tests I've been using the ceramic setting. Though its called an automatic kiln, the only automatic thing about it is the firing setting; the timer on this kiln is only a fail-safe shut off, little more than an egg timer, and the kiln doesn't have the manual option switch that other Teacher Plus kilns have. At this point, I think my saving grace has been that the pieces I've fired thus far have been drying literally for months. But if I'm not getting rid of all the organics then I do have a problem, don't I?

Might be what he meant but I think I saw a similar thing in the kiln manual referring to cone; will need to look again to make sure. Could it be they are referring to a biscuit fire instead of a bisque? I am only learning the difference in those terms from watching the Washington Street Studios YouTube channel--they go into a lot of history as well as chemistry and physics. I guess these days most people fire low for bisque and higher for glaze; apparently a biscuit fire does the opposite--higher for bisque than for glaze. Not sure why things are done differently now--new glaze technology, perhaps? Just did another bisque test, this time with cone packs in three areas (2.5 shelves stacked 5-6 inches apart) and partially loaded with a few pots on each level. I used 06 witness cones and guard cones at 05 and 04. It reached cone 06 in just under 5 hours (my first firing in empty kiln it was around 4.5 hours). This time my 06 witness cone on bottom shelf at the center looked like a decent optimal burn--nice arch--and the 05 cone and 04 guard cones looked factory new. The 06 cone on the edge of the bottom shelf (opposite the sitter) looked tired and droopy and the 05 guard cone had a slight lean to it; 04 looked untouched. Middle shelf had 06 cone quite overdone (reposing elephant pose) and the 05 cone had definite lean to it of about 15 degrees. Of course I forgot to put the cone pack on the upper half shelf! So although it's reaching temperature, it's doing it pretty quickly and its just a bit hotter than target in most places--ie, the outer edges of the shelves and on the higher ones (makes sense I guess). Should I be concerned about the speed? The pots seem to be okay.

I'm a newbie potter and recently purchased my own Duncan teacher plus kiln secondhand from a guy who repairs kilns, so I was glad to get directed to an owner's manual on this thread. I tried the link but it's no longer working--I get that 404 message: essentially an internet dead-end, and Paragon is currently not answering the phone due to COVID. So I decided to wing it by doing a series of test fires and logging what happens. BTW my kiln doesn't have that toggle switch at the bottom--just a dial that turns counter clockwise with three settings: Over-glaze, Ceramic and Hi-Fire. Guy who sold the kiln told me--incorrectly as it happens--that I was supposed to bisque fire at the same cone as the clay; so Cone 5 clay needed a Cone 5 bisque cycle. (Good thing I double checked with an actual potter!) Without a manual I had no idea which setting to use for bisque firing, so I put it on Ceramic, used an 06 bar, set up two shelves, threw a few shards of green-ware all over them, and put an 06 witness cone on each one to see what would happen. The kiln switched off in just over 4 hours, bar was sharply bent, top witness cone looks like a tired elephant, lower witness cone has a good arch but dips a little low (I had set them on potsherds). So, I am guessing I needed to use the overglaze setting to do a bisque firing. Good news is it DID hit cone 06 with no difficulty, and my pieces were properly cooked even if the final temperature seems to have been a bit higher than planned (possibly heated up too quickly? Any thoughts on this?) So, one other question I have about this model. Since it's technically automatic, I'm particularly interested in learning whether its possible to play around with firing routines. Has anyone ever changed a setting mid-firing? I mean, I wonder if it is wise, or possible, to start at a Hi-Fire setting, and partway through switch to a lower setting to get the effect of a "hold" such as you might have on a programmable kiln. I don't want to experiment with that kind of thing if it will do damage, but I would be interested if you, Neil Estrick, might have some ideas about what kind of flexibility can be had with this kind of kiln.