Frogesan Posted October 10 Report Share Posted October 10 Is there a way to reduce thermocouple spalling? Last firing I had little black bits scattered all the way to the center of the kiln (28" kiln) on the side where the thermcouples are. Fortunately, the kiln was only lightly loaded and the bits didn't get stuck in any glaze. However, I'm getting ready for another glaze firing and don't want any glazed work ruined. The thermcouples are the kind that are completely encased in tubes (L&L kiln). I shopvac out the tubes with a brush after each firing, so there weren't any old spalled flakes left in the tubes. I'm perplexed because my old kiln (Skutt) had exposed thermocouples, and I only saw a few bits every now and then. I'm getting ready for another glaze firing and don't want anything to get ruined. Thanks! - Amy Quote Link to comment Share on other sites More sharing options...
neilestrick Posted October 10 Report Share Posted October 10 Are they the closed end tubes or the open end tubes? If they're closed end, then the black spots aren't from the thermocouples. If they're open end, then the thermocouples need to be set back about 3/8" to 1/2" inside from the ends of the tubes. Quote Link to comment Share on other sites More sharing options...
Frogesan Posted Sunday at 08:44 PM Author Report Share Posted Sunday at 08:44 PM The tubes are open-ended. The thermocouples are 3/8" inside the tubes -- should I move them back further? Thanks, Amy Quote Link to comment Share on other sites More sharing options...
neilestrick Posted Sunday at 11:37 PM Report Share Posted Sunday at 11:37 PM 2 hours ago, Frogesan said: The tubes are open-ended. The thermocouples are 3/8" inside the tubes -- should I move them back further? Thanks, Amy I've never heard os thermocouples spitting that far, especially when they're in tubes. Typically they just flake downward. Are you sure it wasn't a glaze spitting? You could try moving them back a little bit. At some point they'll start reading a little cool, though, so watch for that. Quote Link to comment Share on other sites More sharing options...
HenryBurlingame Posted yesterday at 04:27 PM Report Share Posted yesterday at 04:27 PM (edited) I also have a new l&l kiln with the thermocouples in open-ended tubes and am experiencing the same thing. A lot of spalling and the black specs shooting as far as the middle of the kiln shelf like you describe. So far nothing has stuck to a glaze thankfully... I was thinking maybe it was especially bad just because they were brand new and I was just hoping it would get better after a few more firings... Pretty sure I am just going to upgrade to S-Type thermocouples once these guys bite the dust. Probably should have just started that way in retrospect. Edited yesterday at 04:35 PM by HenryBurlingame Quote Link to comment Share on other sites More sharing options...
Hulk Posted yesterday at 05:05 PM Report Share Posted yesterday at 05:05 PM I'm vacuuming the bits out from the previous each time - there's some flakes and tiny bits, very like what falls off the portable I was using. It's nice that the open tube catches most of it. The little bits I'm seeing elsewhere, my guess is they fly out well into the cooling cycle, for they aren't sticking - I haven't yet found a stuck speck that looks like a TC spall... Quote Link to comment Share on other sites More sharing options...
neilestrick Posted yesterday at 07:00 PM Report Share Posted yesterday at 07:00 PM Set the thermocouples into the tubes about 1/2" and see if that helps. Quote Link to comment Share on other sites More sharing options...
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