cadenrank

As always, and again, thank you everyone for the responses. 

@neilestrick I was thinking about trying it. This last maintenance project has taken this kiln out of service since New Year's (mostly just waiting for parts), so the thought of just firing it and just keeping an eye on it and seeing what happened after crossed my mind, but I already had got the old one off, and got the plenum cup clean. I could still put the old one back on (It still has the uncured silicone all over it) but I already ordered a new gasket. I might put it back on just to bisque while I'm waiting for the new one and then clean the plenum cup again later if it doesn't cure still after firing. 

@Rae Reich I saw that when I was googling it. I found a JB Weld 100% Red silicone one that's rated for 650 that's available at an auto parts store nearby, so I'm probably going to go that route when the new one comes.

I think I got my red silicone at the auto parts store 

Common at big box stores - pretty common use in condensing furnaces and boilers. Up to 650f is what I see mostly.
https://www.homedepot.com/p/RectorSeal-Hi-Temp-Red-Silicone-Caulk-57500/202809239
 https://images.thdstatic.com/catalog/pdfImages/a0/a0b46b08-2550-4bd5-acd8-38b1768a8217.pdf
If it’s uncured silicone you likely can remove fairly completely with most solvents, just like cleaning up after application.  I assume the gasket is high temp but not quite enough to infill the gap at the kiln so it’s supplemented with silicone.
“I'm wondering why most suppliers sell one for the gasket that's only rated for 400.” 600 is most definitely better than 400 but it’s at the bottom of the kiln and the pickup cup brings in outside air adjacent to this joint so this connection is not super hermetic really. What lifespan are they shooting for - who knows.
 

I would just leave the stuff on there and put it up under the kiln. It's really just there to hold the gasket in place while placing the cup. Once it's in place the gasket won't move. The heat of the kiln will likely dry it out over time, but even if it doesn't it shouldn't affect anything.

Hello all! 

Today, I got the 8 awg cable that supplies my one kiln upgraded to a 6 awg cable. The intention of this is to upgrade my elements to a different resistance configuration that will both supply the kiln with more power and hopefully more even heating, as well as make replacing elements easier (as I won't need to get them custom made, and hopefully won't have to do any stretching of elements, discussion of this project for this kiln has happened in the past on another topic of mine here, but about time for new elements, so progress towards getting the circuit ready for that transition is underway) 

This kiln currently pulls around 30 amps (8 sided, 5 brick layers deep. Skutt 822 is the most  similar model.). At the end of this project, it should pull roughly 34.7 amps, with the new elements on the 6 gauge copper, and a 50 amp breaker circuit that's now finished for this kiln.

During my last element change I used some of these types of connectors: 


I like these connectors because of how easy they are to connect, and they allow for changes to happen and repairs to happen much more easily than the crimp on connectors. My issue with these is that over the life span of these elements, I've had 4 of the 10 fail. They corroded, and eventually burnt out at the connector, leaving them unusable because the wire had melted where it burned out and essentially welded the connector to the element tail.

This kiln is an older model kiln with entirely new components and wiring. The kiln originally came with brass nuts, bolts and washers as element connectors which I wasn't a big fan of at first, however, of all the types I've tried (the ones pictured, Skutt's crimp on barrels, and Paragon's version (which I mostly don't like because of cost)), I think the nut and bolt connector is the one that I like, and feel the most comfortable with. All of the connectors like the ones pictured above that have burned out I replaced with the old original brass nut and bolt and washers that I saved, and they still look perfect and feel the most secure to me while being relatively easy to perform repairs or replacements with in the future. 
So that being said, my question comes down to material. I don't have enough of the original brass nuts and washers to do the whole kiln with them once the new elements go in, so I'll need to purchase more and I'm just wondering what size as far as bolt goes, material they're made of, etc.  Is brass the best option? Stainless? Are the brass nuts/bolts/washers I'd find in big box hardware store good to handle the heat and voltage/amperage that will be passing through it? Any other recommendations on where to get some that would if not? 

Thanks as always for any information and any help!
-Caden

How about copper split bolt connectors . Electricians like me use them on all large wire connectons as they are made for large amp draws. They are usually all copper and a brass nut. They are spendy and come in a variety of sizes. Also I use copper coat on these connections as that keeps out all corrosion. Never had one fail.

This may help - I like those as well but their mass is small so I personally have seen them fail on the highest loaded elements in the least cooled ares. They are not big enough or have enough surface area to keep the connection cool for the amount of cooling  air passing them.
Improving the cooling airflow can help if the convective flow from bottom to top can be improved. Reducing leaks out of the kiln by stuffing with high temp insulation can help for radiant and convective losses as well.
The simplest solution has been to extend the element pigtail more and position for best convective cooling, just to get some additional cooling to the connection.
conductivity plays a role so copper best, brass next,  followed by steel / stainless.  An old easy connector to build  is drill a brass bolt, use the bolt and two washers. Sandwich the wires between the washers through the drilled hole. Increased  convective cooling (heat sink)  easy to achieve this way, thermal conductivity less of an issue but surface area as well as mass very important. So this can be done with steel and stainless, just harder to fabricate and not thermally as conductive.
1/4” - 3/8” X an inch or two (Cooling surface area and mass) simple brass bolt and nut depending on the clearance in your cabinet can last forever and be very economical and easy to build.

I've had good luck with the connectors you show above, and ConeArt uses them in all their kilns. Are those tinned copper? I usually use raw copper, as does ConeArt. Not sure if that matters or not. One tip, make sure you're putting the wire at the bottom in the V and the element at the top, so the bolt pushes on the element. That'll give a tight connection. You may also need to re-tighten them after the first few firings just to be safe.
Bending the end of the element into a circle and putting a bolt through it is a great connection. Use stainless steel, put a washer on each side, use a lock washer, and connect the feeder wire to it with a high temp ring terminal. Totally old school and very good. I'd use a 10-24 bolt.

@neilestrickI cleaned it up with some emory earlier. Will try the ring terminals and a bolt. Just needs to last until I replace elements. 
Thanks again everyone. Will update how it goes. 
 

I like the bolt method, too. With high temp ring terminals and washers on both sides it's a pretty secure system. Very low corrosion factor with stainless hardware. Similar to the L&L system but without the porcelain block.

Clean up the end of the element with a grinder like Mark said. The high temp ring terminal with a bolt through it should work.

I like the euclids two screw barrel type
see if they will work for you. I keep a stock of them when needed.
https://euclids.com/collections/connectors-lead-outs
 
One trick I have used when trying to reuse the  element with a crimp connector on it is to grind off that connector with a small angle grinder so as not to shorten the pigtail on the element at all . If you go slow and then use some sharp electrical dikes it pretty easy to leave the elenment pig tail full length.
I have replaced all cramp connectors with the Euclid barrel type as they work so much better. If you need a small one (I see thay are out now-I can mail you one) Or I can measure to the screw and see if it will grab tor pig tail (1/4 inch you say) Let me know via a PM.
We are in a huge wind storm  right now and the power is out (not for us - as we have a generator) Bomb wet cyclone is bearing down on us this am.Been wild with two large earthquakes  (one on new years the other Dec 20th) and this is our second atmospheric river to hit us in a few days.I am slowing finding earthquake stuff (no real damage yet)

I'm sticking to the #6 wire and a 50 amp breaker. If you want a 40 amp breaker fine smaller breaker is the safety in this case
I have had 4 skutt kilns in 5 decades and they underrated the old ones badly. I blew breakers and melted a J box ,overheated wires in the 70'sand 80's Upsided the wires all to #6 -hardwired the kilns and zero issues since.
I said it before- bigger wire is always better.
This was my experience . I also learned the top cone the kiln plate  spec was overrated as well and was really not accurate, say cone 8 for example in an old 181 or 231 or a 1227 with 2.5 inch wall.
The plugs between sections wore out fast (from heat) as did the elements.
Of course Skutt discontinued this old plugs between sections to newer better materials
Skutt always overrated those old kilns on the spec plates
I have learned that spec plates are not always right. 
In todays kilns, get a cone 10 kiln for cone 6 fires not a cone 8 kiln for cone 6 fires.
Once you melt a few wires and boxes and toast a few breakers one usually gets it.
I think the newer Skutts are more acurate in terms of specs. Better 3 inch walls and wiring now.

I just happened to look in the latest manual. The math, code requirements, and current Skutt manual seem to all agree so not sure what any distributor is saying but could be an error or a result of previously using lower system volts. Older manuals seem to show it as #8. I guess the lesson is always double check the math, pick an appropriate breaker and pick the wire. The more heating in the wire, the less heating in the kiln. Bigger is usually better for the kiln owner.
If you are using roamex then the wire size will likely be larger. The adjacent conductors in a confined space tend to heat more and are derated from free space. 
The rule about breakers is all about reducing the heating on the breaker so it remains dependable. Heating in wires and devices is not really good.

I don't know why Skutt lists it that way. Skutt also does not list the breaker size, only the wire size and the plug configuration. Many kilns that do not actually pull ~50 amps still have a 6-50 plug on the power cord because that's their standard power cord inventory for all their medium and large kilns. The comparable L&L kiln (e18M) lists a 50 amp breaker and 6 ga. wire.

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)

THHN is better wire (needs to be in conduit( this is more about the wire insulation  type and strands . The better insulation takes more heat and costs more.I use a lot of THHN in life when pulling wires to pump sheds and conduit runs.
NM Romex would be fine for a 30 amp kiln with the 125% rule
50 amps use #6 wire as that covers the 125% rule-you can still use the 40 amp breaker but it may trip and you will then need a 50amp
when it comes to wire size you are far better off to go big. (yes it costs more but kiln use demands it)
 

Maybe old school …. Get a 240 vac miniature pilot indicator, hook it to the output of the SSR and L2 neatly and visible. Get a cheap 12vdc miniature pilot lamp and hook it to the control voltage. They both should light and extinguish unless the SSR is stuck on. Neatly done, should be visible through the ventilation slots, different colors so you can tell which is which. Old school, telltale! Keep neat and away from kiln heat. Remove when finished testing.
 

The transformer is a pretty passive device with a fixed ratio of windings. More likely the input voltage is high, so then why? That goes to does it measure the same as the mains voltage, does the home have an open neutral, etc….. from there if still really high a call to the utility company as you should be limited to 240 vac +/- 10% I believe.
Grounding is something I would confirm for sure as it will be used to mitigate any noise on the thermocouple input. Use of an unbonded  neutral for the ground can cause noise issues.  It needs to be a good earth ground.
Since this can still point to thermocouple input issues I would double check that the thermocouple does not contact the metal case. I have seen them inserted a bit off center and when the kiln heated the side of the thermocouple would just touch the metal of the kiln creating all sorts of random noise.

In case anyone was curious of the outcome, she called Skutt today, which had her repeat some of the tests (including the vDC test on the mechanical relay's control side, meaning the Skutt tech also would have seen the 16.5vDC and didn't say anything relative to it) and conclusion was that the mechanical relay was defective, and they're sending a replacement. 

Pedantically, as P=V^2/R  wouldn't a change from 12v to 16.5v to increase the power by a factor of (16.5/12)^2 = 1.89?
I've no idea how much this would change the operational life of the relay though.

The high voltage wires. I don't know if it's corrosion/oxidation or resistance (or both), but it's definitely a heat issue. I don't ever change out the low voltage control wires unless there is visible damage or they're really old and crispy, like when I rebuild an old control box. A Skutt wiring harness includes the wires going into and out of the relays, control wires, but not the element feeder wires. Feeder wires can't be changed easily since Skutt uses crimp connectors, and they don't seem to be the issue when it comes to relays burning out. Bad feeder wires can cause trouble at the element connection, though.

Not sure either but not sure how common. Interestingly that relay is 14 ohms. At 12 volts it draws 0.86 amps, at 16.5 volts it draws 1.18 amps. The max continuous coil temp of the relay is 40c or prox. 129 degrees f. Basically hot water temp. One thing I know for sure, 16.5 volts will heat that coil  a bunch more than 12 v and the 40c temp limit by the manufacture isn’t a whole bunch. I would be really interested in how many kilns actually run at this control voltage level. Honestly Never really gave it much thought when measuring, I think it’s always been in the 12 v range for me else I would have stopped to understand.
Bad low voltage control wires ought to lower the voltage to the relay or simply be an open circuit. Bad high voltage control wires definitely can cause heat in the wire and heat at the connection which in turn heat the relay. A usual good way to spot is any infrared measuring device used to compare heating in like loads.
Top relay below has marginal connection causing 220 + degree local heating in the relay and wire end.
 

You will ALWAYS measure some random voltage this way for this kiln in its present state,  it’s not accurate in any respect other than to say there is some leakage which we already know because the relay manufacture says it will.