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offcntrI spent the better part of two days this week, while the kiln was cooling, working on the other kiln, my electric kiln at home. It's a Skutt 1227 PK, the professional model, capable of reaching cone 10. It's also older than dirt; I bought it used from a potter who'd had it in storage for a decade or more, so it was in excellent shape, but it was one of the first generation to have a computer controller, and when I contacted the manufacturer to find out how to remove the redundant Kiln Sitter--the original owner was a belt-and-suspenders kinda gal--they had to go deep into the basement archives to find the wiring diagram.
So I suppose sooner or later, it was going to need repairs. Bisque firings were taking substantially longer, and the last high-fire I attempted failed entirely.
My studio is a little too cramped to repair a kiln in, so I waited for reasonable weather, Tuesday afternoon after the fog lifted, to set up out in the car port. First job was removing all the old elements. Newer models use crimp connectors that need to be cut off to separate the elements from power leads. This one used little screw-and-block connectors that were actually easier to undo--except for the one that was rusted solid so the set screw broke off. Once they were all off, it was a matter of finding and pulling out all the element pins with a pair of needle-nosed pliers, then removing the elements.
This model has three rings of brick, two elements per ring, and three different sets of wires. One pair is for the top and bottom elements, one for the two center elements, and one, labeled "Intermediate" for the spaces between. Taking them out, I could definitely tell the difference. Top and bottom were much heavier gauge, and much more brittle. It's a good thing I didn't need them for anything, because they came out in pieces.
The Center elements were still quite flexible, and came out in a continuous pull; the Intermediates were also flexible, but both of them seem to have burned through at some point. This is probably why the kiln was firing so poorly--two of the six elements weren't heating! I had to dig bits of slag out of the soft brick to keep something similar from happening again.
Once elements were out, I vacuumed the brick channels, threaded the new elements in, pinned them in place on all the corners--Skutt is kind enough to pre-bend them at all the corners, making it easy to see how they fit in. I also added a few extra pins in places where they didn't want to lay down in the grooves, vacuumed them again, and connected the power leads.
Had everything finished and ready to reassemble by supper on Wednesday, except for the power leads on the center ring, which needed a replacement connector. Went down to Heinke Electrical Thursday morning; they no longer carry that style of connector, but they sold me a high-temperature crimp connector for 35¢. I also took a piece of Halloween candy out of the bucket on the counter, so they may have lost money on the deal.
Had a bit of a tussle getting the leads into the block in the control box--one thing the new design does much better, giving each set of leads its own little connector, rather than stuffing three thick wires into a cramped screw block--but with a little help from Denise steadying the box, I finally got it all back together. Turned the breaker back on and didn't get an error message, so I guess it's ready to fire again.
So I suppose sooner or later, it was going to need repairs. Bisque firings were taking substantially longer, and the last high-fire I attempted failed entirely.
My studio is a little too cramped to repair a kiln in, so I waited for reasonable weather, Tuesday afternoon after the fog lifted, to set up out in the car port. First job was removing all the old elements. Newer models use crimp connectors that need to be cut off to separate the elements from power leads. This one used little screw-and-block connectors that were actually easier to undo--except for the one that was rusted solid so the set screw broke off. Once they were all off, it was a matter of finding and pulling out all the element pins with a pair of needle-nosed pliers, then removing the elements.
This model has three rings of brick, two elements per ring, and three different sets of wires. One pair is for the top and bottom elements, one for the two center elements, and one, labeled "Intermediate" for the spaces between. Taking them out, I could definitely tell the difference. Top and bottom were much heavier gauge, and much more brittle. It's a good thing I didn't need them for anything, because they came out in pieces.
The Center elements were still quite flexible, and came out in a continuous pull; the Intermediates were also flexible, but both of them seem to have burned through at some point. This is probably why the kiln was firing so poorly--two of the six elements weren't heating! I had to dig bits of slag out of the soft brick to keep something similar from happening again.
Once elements were out, I vacuumed the brick channels, threaded the new elements in, pinned them in place on all the corners--Skutt is kind enough to pre-bend them at all the corners, making it easy to see how they fit in. I also added a few extra pins in places where they didn't want to lay down in the grooves, vacuumed them again, and connected the power leads.
Had everything finished and ready to reassemble by supper on Wednesday, except for the power leads on the center ring, which needed a replacement connector. Went down to Heinke Electrical Thursday morning; they no longer carry that style of connector, but they sold me a high-temperature crimp connector for 35¢. I also took a piece of Halloween candy out of the bucket on the counter, so they may have lost money on the deal.
Had a bit of a tussle getting the leads into the block in the control box--one thing the new design does much better, giving each set of leads its own little connector, rather than stuffing three thick wires into a cramped screw block--but with a little help from Denise steadying the box, I finally got it all back together. Turned the breaker back on and didn't get an error message, so I guess it's ready to fire again.