Lizardman

Yeah, I figured "it depends" was going to be the answer to most of those questions. I hadn’t realized that holds, type of clay, venting, etc. affect element life, but it makes sense. Thanks! I have a set of relays and a thermocouple already on hand and will go ahead on the plan to get spare elements before I need them. Thanks for such a quick, detailed answer (and on a Sunday afternoon!)

I know new elements are in my future, but I’m wondering if there is a way to estimate how soon. I bought a used Skutt 1027 (cone 10 version) in August 2020. I checked the element resistance when I bought the kiln — the top 2 elements and the bottom 2 elements measured between 14.3 and 14.5 ohms (Skutt says these, if new, would measure 13.6 ohms), and the middle 2 elements measured 16.9 ohms (16.3 ohms if new). Since then, I’ve fired it 45 times, no higher than cone 1. Firing times have been pretty consistent, but I want to do some cone 6 work soon so I thought I’d check the resistance again today. Elements 1, 2, and 5 were 14.7 ohms, elements 3 and 4 were 17.2 and 17.3, and element 6 measured 14.7-15 ohms (couldn’t get a steady reading.) According to the 10% rule, I think should expect to replace the elements when the resistances measure about 14.96 and 17.93 ohms. So it seems like I should be able to get to cone 6 just fine, maybe a little slowly, unless the bottom element is a problem. Anyways, to finally get to my questions: 1) Does element life decay at a linear rate? 2) Is there a way to estimate how many cone 6 firings I’ll be able to do before replacing the elements? 3) I’ve read to expect 125-150 cone 6 firings with this kiln before it needs new elements. I assume that # is actually counting the times the kiln gets up to cone 6, not ~65 times to bisque temps and another ~65 glaze firings? 4) Is there a similar rule-of-thumb for # of low-fire firings I’d get out of new elements? 5) Finally, I’m probably going to order new elements this week so I have them on hand for when I need them, unless this is a bad idea for some reason. Is it?

I vacuumed very thoroughly, but thanks for the reminder!

Thanks for the quick answer! I’ll bisque a new waster slab for the sculpture’s glaze firing — better safe than sorry. Measuring is a good idea. I put grog under a waster slab for a recent piece, and when the slab broke it skidded several inches. There was grog in the element grooves all the way down that side of the kiln! I thought maybe I’d over-done it with the combo. The coil method has never made sense to me because the clay is shrinking in all directions and the coils can only roll in 2 directions, but I’ll give it a try some day.

I have made a largish-sculpture (prob. 20 lbs after bisque firing) and some wall pieces, The wall pieces are slabs with shallow "walls" (about 1.25") so they stand clear of the wall and the lugs/wire for hanging are hidden. I bisqued 1 wall piece flat-side-down on a thin waster slab of the same clay body and then glaze-fired it flat-side up on the same waster slab and it worked great! (Well, the waster broke, but that was the point.) The waster slab I put under the sculpture broke into about a dozen pieces, so it isn’t re-usable. I’ll roll out another waster slab for the glaze firing, but I don’t know if I’ll should bisque it first. Additional question: one of the waster slabs I made for a wall piece broke when I moved it. It’s about 17-18" diameter, and a piece along one edge about 1" wide broke off. The wall piece should be almost completely supported by the waster since it’s a little bigger than the piece. Do I need to make a new waster slab? Should I put the broken-off bit next to the rest of the waster? Other, possibly relevant into: The wall pieces are bisqued at ^1 and glazed at ^04; it’s a ^5 clay. I’ve fired hundreds of wall pieces made from this clay at these temps and it works very well for what I’m making. I use full shelves. HOWEVER, these are the first I’ve built with the walls/rims — the others have all been completely flat and I fired them on grog, no waster slab. The sculpture is a ^04 clay, so bisque firing was to that temperature and I’ll glaze fire it at ^04, too. Final question: do I need to put grog under the waster slab? Thanks for your advice!