thermocouple brand?

[moonzie]

Specific to type K, is there any difference between the Ceramic Shop brand and L&L brand TCs? Gauge size/life span?

I'm purchasing parts to convert an old Duncan to digital. Already ordered a transformer and some Crydon SSRs from Mouser.

[neilestrick]

Any of the type K 8 gauge thermocouples will work fine, whether L&L, Skutt, etc.

Are you building a wall mount box? Are you setting it up with zone control? 

[moonzie]

It will have zone control yes. I've got a full size Genesis controller (the older one). 

I might build a wall mount box. I might just put it where the kiln sitter used to be and use a case fan to circulate ambient air. Not sure yet! I suppose a wall mount would give me more modularity.  It's big. ES1020-1 with the added ring on top.

[neilestrick]

2 hours ago, moonzie said:

It will have zone control yes. I've got a full size Genesis controller (the older one). 

I might build a wall mount box. I might just put it where the kiln sitter used to be and use a case fan to circulate ambient air. Not sure yet! I suppose a wall mount would give me more modularity.  It's big. ES1020-1 with the added ring on top.

I'd go wall mount. It'll be easier to work on and everything will stay cooler and last longer. The Duncan box will be a tight fit, and may not be deep enough for everything, plus you could use the wall mount on other kilns in the future. You'll still want a cooling fan in the wall mount, unless you have a large heat sink. A fan is much cheaper than a heat sink. The fan can connect to Output 4, or just run it in line with a power switch. Run mechanical relays in pairs with the SSRs, with the mechanicals being controlled by the Safety output on the  controller and the SSRs run by the Outputs. Use very fast acting Type T fuses for each circuit. The SSR control for the Genesis can be turned on in the Factory Config menu, use code 443.

[moonzie]

Ooo I like the idea of using a pair of mechanical relays connected to a safety output! Or maybe just a beefy double pole single throw relay. The SSRs I ordered are rated for 50a so they should run a bit cooler.

That Duncan is only a cone 8 kiln so I'll probably just use it mainly for bisque fires with the occasional/rare glaze fire for extra large pieces. Lots of elements to maintain. They all appear good but I've got a few new old stock parts on-hand it came with just in case. A part of me wonders if I'm going too far if this is going to be a mostly bisque kiln. I had to calibrate a kiln sitter once on my wife's first kiln (an old L&L from 1971) and I hated it lol. That kiln was never right after she over-fired it one summer.

[neilestrick]

2 hours ago, moonzie said:

Ooo I like the idea of using a pair of mechanical relays connected to a safety output! Or maybe just a beefy double pole single throw relay. The SSRs I ordered are rated for 50a so they should run a bit cooler.

That Duncan is only a cone 8 kiln so I'll probably just use it mainly for bisque fires with the occasional/rare glaze fire for extra large pieces. Lots of elements to maintain. They all appear good but I've got a few new old stock parts on-hand it came with just in case. A part of me wonders if I'm going too far if this is going to be a mostly bisque kiln. I had to calibrate a kiln sitter once on my wife's first kiln (an old L&L from 1971) and I hated it lol. That kiln was never right after she over-fired it one summer.

Each section would have a mechanical relay and an SSR. The mechanical is turned on by the safety relay at the start of the firing and remains on until the firing is done. The SSRs are connected to the  controller outputs 1,2 , & 3 and get cycled on and off by the controller. I've attached a wiring diagram for a Skutt SSR kiln, which is how it should be done.

 

KMT1227-SSRPK-1ph-W_9601.pdf

[moonzie]

Several months later I found I had to use this kiln in a pinch for production untested. Luckily, it seemed to do just fine. The bisque firing it did was all under-fired but that wasn't a big deal. I've read that you should put a cone 6 bar in the Dawson Sitter to fire to cone 5 in this big ol Duncan. These bars were not Orton brand - came with the kiln who knows how old they are. It flattened all of the large self-supporting cone 5 witness cones - like really smooshed it. It did this in about 11 hours. The bisque only took 8 hours I think. I did another glaze fire this time I just put everything on high fire from cool with an actual Orton brand 5 bar and all my witness cones appeared underfired, maybe hit cone 4. Anyways.. I'm pleased the bones were healthy.

 

Curious as to why in the electrical diagram the safety relays are AFTER the SSDs... I'd think it'd make more sense to put the safety mechanism closer to the source of power.. ?

I still want a bigger L&L but wife says we have what we need with this one lol.