Mark C. Posted February 23, 2022 Report Share Posted February 23, 2022 Move the thermocouple-fill the hole and drill a new hole -easy fix on that issue. Link to comment Share on other sites More sharing options...
cadenrank Posted February 23, 2022 Author Report Share Posted February 23, 2022 14 minutes ago, Mark C. said: fill the hole and drill a new hole What does one fill a hole in the brick with? Link to comment Share on other sites More sharing options...
Bill Kielb Posted February 23, 2022 Report Share Posted February 23, 2022 4 hours ago, cadenrank said: What does one fill a hole in the brick with? Green patch, soft brick and green patch, in a pinch fiber. Link to comment Share on other sites More sharing options...
cadenrank Posted March 10, 2022 Author Report Share Posted March 10, 2022 Alright, so I've run the test with cone 5 in the sitter, and while my predictions of top and bottom shelves being roughly a cone 5 , and the middle shelf being a perfect cone 6, I wasn't satisfied with the colors on the top and bottom shelves. It would appear that I have a preference for my glazes at cone 6. Middle shelf was perfect. (Also adding: using cone 5 in the sitter like this also rid of the bloating, as expected. Just to confirm that was the issue) So, I decided to swap the middle ring to the bottom, and what I thought was going to be the issue, turned out to be the opposite. I originally thought the thermocouple in the middle ring would be the issue, but actually the sitter now in the middle of the kiln is the issue. I have two ways that I typically load this kiln, either a 7 inch section on the bottom, 7 inch section in the middle and then all the top space, or a 6 inch on the bottom, and a 7 inch in the middle, then the top space. In either configuration, after the first 7 inch or 6 inch posts, the shelf is either right in front of the sitter, or right above it, which I don't particularly like, and this is with the kiln not packed full. I plan to run a test in this configuration tomorrow or the next day to see if it achieves better balance to cone 6. The thermocouple is in a good spot in the bottom (pretty much how the sitter used to be) and is a good ways away from anything, but the sitter is in a very annoying spot. I'm just thinking, if this doesn't work, what is the other options? Pull the elements out of the middle ring (which is now on the bottom) and replace them with maybe 40 ohm elements instead? I'd hate to do that(just because these elements are only a month old) but as of now, every configuration has some sort of issue. That would put it at 6amps in the middle, and roughly 6 amps for each 4.5 inch section of brick, taking the whole kiln down to exactly 30 amps. From our current 30.86 amps. Any other ideas? Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 10, 2022 Report Share Posted March 10, 2022 2 hours ago, cadenrank said: I'm just thinking Only have one question. How fast did you fire in the last 200 degrees? Link to comment Share on other sites More sharing options...
cadenrank Posted March 10, 2022 Author Report Share Posted March 10, 2022 1 minute ago, Bill Kielb said: Only have one question. How fast did you fire in the last 200 degrees? During this last time with cone 5 in the sitter, I just used all of the switches on high. I believe it took around an hour to get from the 2000 mark to the time the sitter dropped at cone 5. The firing took roughly 6 hours total. I didn't attempt cone 6 with the middle switch consistently on a lower setting, mostly because I had cone 5's available, and I didn't want to take the risk of overfiring the middle shelf again. Link to comment Share on other sites More sharing options...
Min Posted March 10, 2022 Report Share Posted March 10, 2022 Apologies in advance if I missed in another thread, is this a kiln you built? Fellow by the name of Jay Clarke at Euclids is helpful in figuring out elements specs for kilns that don't have stock elements. If you send him some photos with internal measurements and the fact that it's a sitter kiln with infinite switches he might be able to give you some advice on the element(s) resistance required. If he gives you some figures you could then compare those with the ohms of your current elements. Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 10, 2022 Report Share Posted March 10, 2022 14 minutes ago, cadenrank said: believe it took around an hour to get from the 2000 mark to the time the sitter dropped at cone 5. The firing took roughly 6 hours total. Glazes, cones and evenness of firing really like the 100 degrees per hour in the last 200 of the firing. That would be 1 degree per minute to a bit less than 2 degrees per minute. I would figure out where I really am first then take some next steps based on that knowledge. Link to comment Share on other sites More sharing options...
cadenrank Posted March 10, 2022 Author Report Share Posted March 10, 2022 Just now, Min said: Apologies in advance if I missed in another thread, is this a kiln you built? Fellow by the name of Jay Clarke at Euclids is helpful in figuring out elements specs for kilns that don't have stock elements. If you send him some photos with internal measurements and the fact that it's a sitter kiln with infinite switches he might be able to give you some advice on the element(s) resistance required. If he gives you some figures you could then compare those with the ohms of your current elements. This is a kiln I've modified heavily, lol. I built the middle ring out of an old blank ring, to add 4.5 inches of height. The rest of the kiln is more so just replaced with brand new parts, but in regards to specs, it's running the same way. I added the middle ring, and I think where I went wrong here was basing it off of the 'balanced' elements that Skutt gives specs for the same size of kiln I'd have after adding the middle ring, and not looking that their specs are running a different configuration than mine (top and bottom in theirs use parallel wiring, mine are 10 ohms, wired in series on the top and bottom). Jay Clarke was the one who supplied the elements for the middle ring, as well as some other parts to complete the project. While I know how I could solve this imbalance now in the future, my goal is not to have to replace all of these elements that are relatively new. (top and bottoms are only 5 months old or so, and middle is a month). 3 minutes ago, Bill Kielb said: Glazes, cones and evenness of firing really like the 100 degrees per hour in the last 200 of the firing. That would be 1 degree per minute to a bit less than 2 degrees per minute. I figure out where I really am first then take some next steps based on that knowledge. I'm going to run this test firing with it the way it is currently with the middle ring on the bottom, and see what the results are. (it's relatively empty, but cone packs on each shelf and some small things here and there in the safe zones). If all fails, I'll either return it to the middle, and try keeping the middle switch lower, or just pull the middle ring until I can do something different with it i.e. put higher resistance elements in it. Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 10, 2022 Report Share Posted March 10, 2022 2 hours ago, cadenrank said: I'm going to run this test firing with it the way it is currently with the middle ring on the bottom, and see what the results are. (it's relatively empty, but cone packs on each shelf and some small things here and there in the safe zones). If a As I said, I trouble shoot in sequential steps, others trouble shoot in multiple steps or jumps. Both methods work so however you come to the conclusion the section is over powered and by how much will eventually reveal what the answer will likely be. I do believe it is a great opportunity to learn how glazes mature and until the last 200-300 degrees where fluxes have enough energy to begin making things happen the firing is essentially reversible as if it never happened. This final rate also lends itself to more even firings as the slower one goes within a reasonable range, the more even things become. Even when a kiln is not super evenly heated. You will find a power reduction level for that ring that allows you to fire at a good rate and is capped at some effective cone because of the total power needed to reach that cone. For now I think we have concluded that that ring produces 20-25% more heating energy than the others so how you mitigate that by position and infinite switch setting will be influenced by your troubleshooting methodology. It will be interesting to see what works best for you, I believe you will need to power that section back a bit so would suggest diligent use of your pyrometer likely speeds up the learning process. Link to comment Share on other sites More sharing options...
cadenrank Posted March 10, 2022 Author Report Share Posted March 10, 2022 7 hours ago, Bill Kielb said: As I said, I trouble shoot in sequential steps, others trouble shoot in multiple steps or jumps. Both methods work so however you come to the conclusion the section is over powered and by how much will eventually reveal what the answer will likely be. I do believe it is a great opportunity to learn how glazes mature and until the last 200-300 degrees where fluxes have enough energy to begin making things happen the firing is essentially reversible as if it never happened. This final rate also lends itself to more even firings as the slower one goes within a reasonable range, the more even things become. Even when a kiln is not super evenly heated. It's currently testing to cone 6 with the middle ring in the bottom. We do know that it is over powered (at least compared to the top and bottom rings), and we know numerically the values in which it's overpowered by in comparison. The top ring (9 inch section) pulls 12 amps, the bottom ring (9 inch section) pulls 12 amps, and the middle ring (4.5 inch section) pulls 6.8 amps. If this test works, (just testing it this way because I already did it, and it was Neil's idea to put the more powered ring on the bottom) it really is just only proving the point of the middle ring being too hot. The issue with this configuration is that having the sitter in the middle of the kiln (even though I understand why that's ideal) puts it in an awful place for the way I typically need to load this kiln. So the liklihood that I'll keep it in this configuration with the middle ring on the bottom is pretty low for that reason, even if when I open the kiln tomorrow the kiln is perfectly even. So, I'm probably going to go back to your suggestion @Bill Kielb and just keep the middle switch on a lower setting the entire firing or at least the last two hours or so and see what I achieve. I both can't keep overfiring the middle shelf, but I also don't have any interest in changing the setup of how I normally pack this kiln, because I feel that any other configuration to avoid the sitter in the middle would drop the amount of things this kiln can hold even further, which in turn just makes it more logical to just remove the middle ring all together again. Just for the future once this time comes around again, what would you think an ideal element configuration would be for this size of kiln? Full (numerical) evenness, with the top and bottom sections wired in series, and similar to the current set up (*trying to keep this kiln to stay around 30 amps*), would be #1 (very top element) 10 ohms, #2 10 ohms (1-2 in series, 12 amps), #3 40ohms (on it's own, 6 amps), #4 10 ohms, #5 10 ohms(very bottom element, #4- #5 in series). This would put every 4.5 inch section of the kiln having 6 amps. That of course is just thoughts for the future, and I'm not sure if numerical evenness is the ideal from what I've learned through this project. I'd imagine, higher power top and bottom, with lower powered middle is the concept, but just looking for ideas. 8 hours ago, Bill Kielb said: You will find a power reduction level for that ring that allows you to fire at a good rate and is capped at some effective cone because of the total power needed to reach that cone. For now I think we have concluded that that ring produces 20-25% more heating energy than the others so how you mitigate that by position and infinite switch setting will be influenced by your troubleshooting methodology. Like I said, likely after this test firing completes I'll probably return the kiln to the prior configuration, and try just keeping the middle switch on 5.5 or 6 during the last part of the firing/the whole firing maybe and see how it goes. Again, I appreciate everyone's help in all of these various projects. I've learned a lot about a lot during the whole process. Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 10, 2022 Report Share Posted March 10, 2022 8 hours ago, cadenrank said: ust for the future once this time comes around again, what would you think an ideal element configuration would be for this size of kiln? F If I look at Skutt’s later element pattern the top and bottom are about 23% less in resistance than the middle which means the middle is significantly less wattage and top and bottom more power. I would be inclined to consider their design direction as a decent starting point. Link to comment Share on other sites More sharing options...
cadenrank Posted March 11, 2022 Author Report Share Posted March 11, 2022 I unloaded this test fire with the middle ring on the bottom, and as I was anticipating, all shelves fired to a pretty much perfect cone 6 with all switches to high. But again, the sitters position in this configuration is terribly limiting. I'm going to continue thinking on it. I believe next step is going to be to return it back to how it was, and try lowering the power in the middle ring and seeing what kind of results I get with keeping the switch lower during the last part of the firing. I'm trying to think if maybe there's a better way to configure the kiln instead of how I do it. Maybe flip my normal configuration upside down so the sitter is in between shelves instead of right at the shelf. I'd have to buy new posts that size, but I'm not terribly concerned about that, but have to think of the logistics of it to work as well as I currently have it running. Anyways, I'll update what I figure out and what I try next. Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 11, 2022 Report Share Posted March 11, 2022 44 minutes ago, cadenrank said: I unloaded this test fire with the middle ring on the bottom, and as I was anticipating, all shelves fired to a pretty much perfect cone 6 with all switches to high. But again, the sitters position in this configuration is terribly limiting Sounds like you found a solution, maybe just relocate the sitter? Link to comment Share on other sites More sharing options...
cadenrank Posted March 11, 2022 Author Report Share Posted March 11, 2022 5 minutes ago, Bill Kielb said: Sounds like you found a solution, maybe just relocate the sitter? Well, relocating the sitter would mean redoing the entire control box for that section as it's built into it. I wish that was a better option, since if it was just an inch or two lower it wouldn't be an issue. I was thinking more so shelf configuration instead of doing a 6 or 7 inch section at the bottom, then a 7 inch section in the middle, then whatever space left up top, maybe figuring out how much exactly that space is at the top, then put that space on the bottom with posts, then a 7 inch, then whatever I have left up top. This way the sitter would (probably) not line up with any shelves or be as close to them as they are in the way I normally set it up. Still contemplating switching it back, and trying with the switch powered lower, though. Trying to figure which one would be the easiest/best solution until the next element change comes around. Shelf configuration seems like it would be easiest, since there's less variables (mostly the fact that this test firing being perfect confirms/solves the balance/overfiring issue, and keeps the firing time), but switching it back would allow me to keep loading it the way I have been without the need to purchase extra posts, and the sitter in a more ideal (in regards to loading at least) position, but has more variables (being I have to test to make sure it does solve the balance issue with the switch lowered, and retains decent firing time + doesn't over fire.). Link to comment Share on other sites More sharing options...
neilestrick Posted March 11, 2022 Report Share Posted March 11, 2022 Sounds like a good time to get rid of the sitter and get a digital controller.... Link to comment Share on other sites More sharing options...
cadenrank Posted March 11, 2022 Author Report Share Posted March 11, 2022 Just now, neilestrick said: Sounds like a good time to get rid of the sitter and get a digital controller.... I'd be lying if I said that thought hadn't crossed my mind. Unfortunately I just had to replace the bottom slab in my other kiln so that was my kiln repair budget for the next month or two lol. Link to comment Share on other sites More sharing options...
cadenrank Posted March 20, 2022 Author Report Share Posted March 20, 2022 I switched the middle ring back to the middle, and I'm currently running a glaze firing to cone 6. I'm trying to keep the middle switch not on high, but the increase in temperature is still very slow. We're only at 6.5 hours at this point, and roughly 2111 degrees F (3:34pm) . A couple minutes ago I turned the middle switch up higher, but still not to high. Prior to that we were at about 60 degrees an hour (my math could be wrong on this, and it's really only based on sampling 15 minute sections) and now it seems like were about 80 degrees an hour, but it's increase is relatively slow either way. Again, the speed seems like when the middle switch is in it's on cycle, the temperature increases pretty consistently, but when it switches to it's off cycle, the temperature begins dropping pretty quickly, and then once it cycles back on it has to make up for the lost temperature (usually 2-4 degrees) and then gain some, before repeating. Of course, I won't know until this completes and I can see all the cones, but I'm not so sure this is going to be an ideal solution either unfortunately. It's 3:39pm now, and the temp is 2118 degrees f. Just to verify my math of calculating degrees/hour, based on a sample. If I sample 15 minutes, taking the temperature I end at, subtracting the temperature I began at, then multiplying by 4, would give me degrees/hour, right? Written out something like: x = start temp at beginning of 15mins, y = end temp at end of 15 mins, (y-x)*4 ? That would come out to if we started at 2000 and then ended at 2025 degrees in 15 minutes would be 100 degrees an hour based on sample? Attached below is a rough graph of this firing up until this current point, based on 4 logged temperature values and their time (in 24 hour, actual time). Adding, 3:48pm, temp is 2130 degrees f. the graph starts at 9:00 am, and ends at 3:38pm. Kiln is still ongoing at 3:51pm. Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 20, 2022 Report Share Posted March 20, 2022 I think your graph is fine. Your rate really needs to stay at 100 degrees per hour in the last 200 degrees so in this configuration it still needs to operate at that speed. The top and bottom are just very underpowered. To make life easy on myself 1 degree per minute is 60 degrees per hour. 2 degrees per minute is 120 degrees per hour. In five minutes I need a 5-10 degree increase to be 60-120 degrees per hour. Five minutes is an ok minimum interval to get an ok picture of what is happening in an hours time or as a monitoring interval. 60 degrees per hour is getting close to the minimum rate needed for consistent predictable heatwork in the last 200 degrees of the firing. I keep mentioning this because once folks understand it, it’s extremely important to firing to cone more easily. It is printed on the Orton chart, but honestly few have been taught it for some reason. Anyway the better one understands, it’s my belief the easier it is to fire to consistent cone. Since you lose temperature excessively during the center element off cycle, your top and bottom rings are significantly underpowered which we knew. If you were proficient, you could take 2-5% of the resistance out of the top and bottom elements at a time until you found the perfect resistance. This technique is a bit risky for old elements and requires torch work to heat red hot anytime a section is straightened or bent. Afterward, your element will not last as long, because it will run hotter, it is just a way to sneak up on the optimal value of these so you can eventually have new ones wound. Lots of risk with this technique and one must pay attention to the new amperage being drawn and all the devices that support this amperage. Just a late add here as you end of firings, the last 200 degrees should take about two hours at 100 degrees per hour rate. So how that fits into your timeline, I am not sure but likely means you need to be able to go 400-550 degrees per hour for the first four hours to be able to end in six hours and fire nicely to cone. Link to comment Share on other sites More sharing options...
neilestrick Posted March 21, 2022 Report Share Posted March 21, 2022 One thing you could try is letting the middle section run ahead of the other sections until the last 200 degrees. The other sections will benefit from the heat of the middle, and the firing will run faster. There's really very little need to keep everything even until the last 200. Link to comment Share on other sites More sharing options...
cadenrank Posted March 21, 2022 Author Report Share Posted March 21, 2022 The firing ended around 4:06pm I believe, so around 7 hours. My ultimate goal is to remain under 8, and get to a cone 6 on all shelves. I also remembered an issue that may possibly be contributing to this issue, that I will address prior to the next firing (that issue being the top infinite switch cycling when on high. I brought it up a month or two ago, and bought a replacement switch for it, but since it was firing so fast, I didn't see the need to replace it. I also don't know if it's still cycling or not, but will replace it to find out. It's possible that maybe it's not just the middle ring dropping out, but the top ring cycling too, which would drop temps even faster if that's happening, but based on thermocouple readings, I don't think this is happening, or if it is, it's happening at the exact same time as the middle switch , which I think the odds of are pretty low). I don't know when the kiln hit 2000 degrees, but I believe it would have hit the last 200 degrees within two to three hours, maybe. At least looking at the graph would show that it was, even though it didn't seem like it. I'll find out what the cones look like in the morning. I'm not exactly certain if my math was right in determining temp/hour. When the middle switch was cycling on, it was probably a degree every 20-30 seconds, but when the switch cycled off, it'd drop, then have to rebuild what it lost, and then would go up one or two from where it lost, so in not a consistent climb to be able to determine exact rate of climb. I don't believe the kiln has any issues in the first four hours (with the middle switch on 6). It climbs consistently even when the middle switch cycles and I believe it went from 150 degrees to 1500 degrees within 2.5 hours. It was once we hit about 1900-2000 that I started to notice the drop in temp when the switch would cycle. (which makes sense) 4 minutes ago, neilestrick said: One thing you could try is letting the middle section run ahead of the other sections until the last 200 degrees. The other sections will benefit from the heat of the middle, and the firing will run faster. There's really very little need to keep everything even until the last 200. I had thought about doing it that way, but was afraid of either A. forgetting to turn it back, or B. not knowing exactly when to turn it back and doing it early or too late. Time frame of when it got to 2000 was relatively quick, but the last 200 took a while it seemed. I don't have the exact numbers (just the estimation from the chart based on the climb) but I know from 1800 to 2100 took about 3 hours. Then it took another 45 minutes or so until it shut off. I didn't see the max temp. Just looking back at those numbers laid out, I think I am calculating degrees/hour incorrectly, but I'm not certain. I know the temp and time are correct, but not sure I'm calculating degree/hour right. This is semi unrelated, but how are elements manufactured to resistance specs? I notice Skutt uses some very odd spec'd decimal numbers for their resistances, can an element be made to practically any resistance? (not thinking in terms of functionality, just in regards to actual manufacturing). Link to comment Share on other sites More sharing options...
Bill Kielb Posted March 21, 2022 Report Share Posted March 21, 2022 4 minutes ago, cadenrank said: This is semi unrelated, but how are elements manufactured to resistance specs? I notice Skutt uses some very odd spec'd decimal numbers for their resistances, can an element be made to practically any resistance? (not thinking in terms of functionality, just in regards to actual manufacturing). Short answer - yes pretty much any resistance by varying the length of wire which coil diameter and coil spacing would be adjusted accordingly. Link to comment Share on other sites More sharing options...
neilestrick Posted March 21, 2022 Report Share Posted March 21, 2022 12 minutes ago, cadenrank said: from 1800 to 2100 took about 3 hours 300 degrees over 3 hours, so 100 degrees per hour, assuming it was ramping at a constant rate. 12 minutes ago, cadenrank said: This is semi unrelated, but how are elements manufactured to resistance specs? I notice Skutt uses some very odd spec'd decimal numbers for their resistances, can an element be made to practically any resistance? (not thinking in terms of functionality, just in regards to actual manufacturing). It all starts with the total amperage. If you look at the typical 23x27 kiln like a Skutt KM1027 or L&L e23T-3, it draws 48 amps total, so 16 amps per section if all the elements were the same resistance like in an L&L. But Skutt is adjusting the draw of each section so the top and bottom elements are running hotter. They've probably figured out that there's a certain percentage that's good for the adjustment, which is why it's a strange decimal number for the resistance. Each kiln company has also decided what they think is the best wire thickness and coil diameter and coil spacing for each element. This can vary greatly, though. Standard L&L elements have very close coils, some Paragon kilns have very widely spaced coils. They all seem to work just fine. I just changed the elements in a Skutt KM1227PK, and there were 3 different elements, and 2 different element thicknesses. I believe a lot of Cress kilns have at least 3 different elements, too. Lots of ways to accomplish the same result. Link to comment Share on other sites More sharing options...
cadenrank Posted March 21, 2022 Author Report Share Posted March 21, 2022 1 hour ago, neilestrick said: 300 degrees over 3 hours, so 100 degrees per hour, assuming it was ramping at a constant rate. Maybe my numbers were relatively accurate, then. I'm pretty sure the 1800 to 2000 degree range probably happened much faster, but the 2000 to end range happened a lot slower. Anytime I was calculating (the equation used in my first response, so still, maybe inaccurate) I wasn't below 60 degrees an hour, and when I saw the trend was slowing down a lot was when I turned the middle switch up to roughly 6.5 from 6. 1 hour ago, Bill Kielb said: Short answer - yes pretty much any resistance by varying the length of wire which coil diameter and coil spacing would be adjusted accordingly. That makes sense. 1 hour ago, neilestrick said: It all starts with the total amperage. If you look at the typical 23x27 kiln like a Skutt KM1027 or L&L e23T-3, it draws 48 amps total, so 16 amps per section if all the elements were the same resistance like in an L&L. But Skutt is adjusting the draw of each section so the top and bottom elements are running hotter. They've probably figured out that there's a certain percentage that's good for the adjustment, which is why it's a strange decimal number for the resistance. Each kiln company has also decided what they think is the best wire thickness and coil diameter and coil spacing for each element. This can vary greatly, though. Standard L&L elements have very close coils, some Paragon kilns have very widely spaced coils. They all seem to work just fine. I just changed the elements in a Skutt KM1227PK, and there were 3 different elements, and 2 different element thicknesses. I believe a lot of Cress kilns have at least 3 different elements, too. Lots of ways to accomplish the same result. I think next time (if I don't end up doing it sooner, because it would solve all of these issues) I'm going to use Skutt's reference to resistance for the equivalent size kiln, and get an input from Euclid's on their thoughts on a good configuration for it. I'd just go ahead and do it, but I hate the idea of pulling less than 2 month old and 1 month old elements out of it. Still trying to keep total amperage below 32 amps, mostly just to keep circuit size the same for this kiln. I am still contemplating increasing the gauge of the wire to this kiln, but am still not ready to go that route yet. Maybe I'll decide on it before the next element change. I'll let you guys know what the results of the cones/work inside of it is tomorrow. I loaded it pretty lightly, and safely so that even if the middle overfired again, everything in the middle are things that are either just tests or things I'm not afraid to lose, and important things on the top and bottom shelves. But obviously, this isn't ideal for what this kiln is normally firing. Link to comment Share on other sites More sharing options...
cadenrank Posted March 21, 2022 Author Report Share Posted March 21, 2022 The top shelf was a cone 6, middle shelf was overfired to 7, and bottom shelf was a perfect cone 6. The middle shelf's cone 6 wasn't bent over as far it was last time I fired in this configuration, but still more than the other two shelves. Link to comment Share on other sites More sharing options...
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