neilestrick

The can handle two kilns, so yes on one kiln they are starved. They work, though. Thousands of these out there functioning as intended...

If the existing motor is swapped for a inline fan with similar CFM but the rest of the system is used as-is, no further modifications would be necessary since the mixing is done at the collection cup under the kiln.

If you get an inline fan, get one rated for the same draw, around 140CFM.

That sounds normal to me. It's just a simple squirrel cage blower, so not the most advanced blower technology. When they go bad the bearings wear out and they make a lot more noise than that. I couldn't hear it in the video, but if you're getting any additional noise from vibrations in the wall, you could put it on the floor on a piece of foam to isolate it more.

Link isn't working for me.

It definitely makes some sound, but you should still be able to have a conversation while next to it. It's possible you got a bad one. Can you post a short video so we can hear it?

You won't get all the elements glowing unless it's on high. Get yourself an inexpensive digital pyrometer and a heavy duty (8 gauge) type K thermocouple from Amazon and stick it in the spy hole to track temperature rise.

Yes, kilns smell when they've sat for a long time. Make sure the control boxes don't have dust and crud and spiderwebs and moues poop in them from sitting. Periodically feel the power cord and plug and make sure they're not heating up too much during the firing. Slightly warm is normal.

Many kiln companies use 50 amp power cords on their kilns because that is the largest size cord that is used on kilns, and they only want to stock one size of power cord. Being larger than is needed isn't a big deal. Electrical code requires that kilns are on a breaker that is 25% greater than the actual amperage draw of the kiln. So you 24 amp kiln should be on a 30 amp breaker. The 6 gauge wire that was run may or may not fit in a 30 amp breaker, though. If it won't fit, code also says that it can be a breaker that is up to 50% greater, so it could be on a 40 amp breaker and still be up to code, and that should fit the 6 gauge wire no problem. As long as the power cord, plug, and outlet are are rated for at least the size of the breaker then you're safe. It's all about the amperage. Your cord has wires that can handle 50 amps. The 6 gauge wire in the wall can handle 60 amps. You just need a breaker that is the correct size for the kiln (30 amp ideally, 40 if the wires won't fit), and a plug and outlet that are rated for at least as much as the breaker. Your electrician probably looked at the Kiln Sitter instead of the serial plate. Sitters are rated for up to 50 amps, so they say '50 amps' on them, but that has nothing to do with the actual amperage draw of the kiln. The kiln is is beautiful condition. Blue Diamond made nice kilns. If you need elements, go to Euclids.com

Skutt does the graded elements to compensate for the fact that most of their kilns are single zone, and the controller doesn't know what's happening in the top and bottom sections of the kiln. It's not nearly as precise at keeping things even as zone control, though, so you still have to be careful how you load the kiln. If you run zone control with graded elements, the top and bottom sections won't have to work as hard as with equal elements since they're running hotter. The total power consumption would probably be about the same, since the total wattage is the same with either setup. It's hard to estimate just how much of a difference it would make. I think it would take a real world test to find out. My gut says it would be more like 75% instead of 85%. I think to get them all to run totally even, you'd have to have a drastic power difference between the middle and the other sections. The Skutt 1231PK runs 3 different elements. I think some of the older Cress kilns do that, too, even on 27" tall kilns. L&L has always run equal elements because it greatly simplifies everything when it comes to elements. No worries about getting the wrong elements in the wrong place, etc. And as a repair person the math is easier if you need to calculate element resistance on the fly. TBH, I haven't noticed the middle section elements wearing that much differently than the top and bottom on my L&L kilns, and I've always gotten about 150 firings between element changes, so it's not really a big deal. I think that just being in the heat degrades the elements a lot, even if they're not working hard to create the heat.

You can still fire by color if you want to. Set it to cone 7 medium speed, then manually turn it off when it hits the color you want.

Feels weird to self-quote, but this made me think of a phenomenon we see in wood burning kilns and sometimes in gas salt kilns, too- kilns that have hard brick interiors. There's often a point at which the kilns stall out, where the mass of the bricks are sucking up all the energy. Then, once the bricks become saturated with heat they start radiating and the kiln climbs easily. In grad school we had a shino kiln that had 18" thick walls- 9" of hard brick interior and 9" of soft brick exterior. The idea was that you'd fire really slow, like over two or three days days so the hard bricks got super saturated with heat, and then it takes days for the kiln to cool, which gives great color in shino glazes. Anyway, my fried was firing the kiln and had it climbing really slowly. After a day or two the kiln was at about cone 6 and should have continued for another full day at that rate of climb, and needed turning up a couple more times. So he went home and went to bed that night and in the morning the kiln had flattened cone 11. We figure it got to cone 14 or higher. The bricks had become saturated and the kiln rocketed up. Anyway, this just popped into my head when I was looking at my firing reports.

The SSR's are really good at keeping it even. In looking at my last few firings, the temp difference between the 3 sections during the final slow rap is never more than 2F degrees. During the faster ramp it's mostly even, but in every firing there's a couple hundred degrees at some point where the spread gets to 10F degrees. It's interesting to see how that varies from firing to firing. Sometimes it goes uneven at 1600F, sometimes at 1900F. It's clear that how each batch is loaded affects what happens during the ramps. I was also surprised that during the final 108F/hr ramp the relay % doesn't vary much over the 200 degrees. It's only 2-4% difference. I would have thought it would be working a lot harder at the peak. 200 degrees is a big climb, after all. I suppose that during the slow ramp the bricks and ware are much closer to the air temp, so they're not just sucking up every bit of energy the elements put out and the elements don't have to work nearly as hard to make gains in temperature despite it getting hotter. I've also seen in several firings that the top section is clearly dealing with heat loss out the lid during the final ramp, as it tends to increase more than the bottom and middle by the end of the ramp. It's fun to geek out on a spread sheet!

It's always time to get the banjo out.

It's not that fast at the final ramp. I explained that poorly, and have corrected it. It can keep up with 350F/hr to about 2050F, but then it starts to lag a little bit. It can keep up 300F/hr up to 2100F, though. That I've tested. When I fire I ramp at 300F/hr to 2030F, then I ramp at 108F/hr to 2230F. At the peak of my last firing, which was a pretty full load, it was running 93% top, 47% middle, 90% bottom. So there's definitely room for more speed but not 350F/hr. I bet it could run 150-200F/hr at the peak. BTW, it's an L&L eQ2827-3, 14950 watts, 41.5 amps on 208V 3P service, solid state relays. One of the cool things about the SSR's is if you get really close to the kiln you can hear the elements buzz in a pulsing rhythm as the relays cycle twice per second. It's like a faint drum beat.

I have found that my kiln can go 350F/hr to about 2050F. It's not because of a lack of power, but rather because for it to go faster than that the middle section will have to run farther ahead of the top and bottom sections than the controller will allow it to. At 2000F and a rate of 350F/hr, the bottom section will be on 100%, the top at about 97%, and the middle at about 45%, and the three sections will be dead even in temp. For the firing to increase in speed, the middle is the only section that can speed up, which would put it ahead of the other sections. The heat from the middle would help push the top and bottom faster, but the middle would also get ahead of the other sections. Personally, I don't think it's a problem for the middle to jump ahead by 30 degrees if you're then slowing down to 108F/hr for the last 200 degrees, because there would be plenty of time for the sections to even out at that point. 350F/hr is plenty fast, so it's not really a problem in terms of the results. That said, it would be nice for the middle section to take some of the work from the other sections so that the elements wear more evenly.

I thought they had a flyer in there?

The factory thermocouple offset of 18F was used with the closed-end protection tubes because the tubes insulate the TC a bit. With the open-ended tubes they started using this year, they do not need an offset because of the tubes since they're open. An offset may be needed for typical calibration reasons, though.

I have my TC's about 3/8" from the end of the tubes, and I haven't seen any flaking into the kiln yet after about 20 firings. Definitely some flakes visible inside the tubes, though. So far so good.

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How is the reduction created in your kiln?

Exactly! It's about due for a cleaning...

They're fun to make, but my arms are killing me! 95% of what I make is under 5 pounds so this is rare. When I do these I center the 12 pound pieces in two parts- center half, add the other half, center all that. It's easier that way, and almost as fast. Saves my wrists a lot of strain. I could just muscle it all when I was younger, but now I try to work smarter when I can.

Nah, I just don't clean my splash pan very often. That mess is from a lot of pots. I work with cylinders rather than sausages/coils. For these I throw a 7# base slab with a 1" tall wall, then stack two 12.5# cylinders (all while wet) and pull and shape. After it stiffens up a little bit, I add another 12.5# cylinder to finish it off. So 45 pounds total.

Making a couple of big planters for our deck.