kash73 Posted November 16, 2016 Report Share Posted November 16, 2016 Hello! I have a smaller Skutt kiln, and I've noticed in my last few bisque (^04) firings, the cones on the top shelf have not bent over completely. I'd read that even though this happens, I could still safely go to glaze (^6) fire. When I do that, all the cones on all shelves (between 3-4) come out bubbled - little air pockets on the surface - and stuck to the shelves. Does anyone know what could be the cause of this? I've researched online and in the Slutt and Orton manuals and haven't been able to solve it. As you can probably tell from this question, I am a new kiln owner, a newb. Any input and suggestions greatly appreciated! I have a photo of the cone sets that I can post (?) if that helps. Link to comment Share on other sites More sharing options...
Mark C. Posted November 16, 2016 Report Share Posted November 16, 2016 Photo would really help here Are the cones melted over and bubbling or standing and bubbling ? Link to comment Share on other sites More sharing options...
neilestrick Posted November 16, 2016 Report Share Posted November 16, 2016 If they're melting down flat and bubbling, no big deal. If they're just bent and bubbling, that's probably a problem. Cones last forever, so age shouldn't matter, but if they ever got wet they can behave oddly and should be thrown out. Link to comment Share on other sites More sharing options...
kash73 Posted November 16, 2016 Author Report Share Posted November 16, 2016 Here is a photo of the last cone sets for both bisque and glaze firings. Link to comment Share on other sites More sharing options...
dhPotter Posted November 16, 2016 Report Share Posted November 16, 2016 kash73, after you "Browse" and select the pic, then you must click "Attach This File", then click "Add Reply" Link to comment Share on other sites More sharing options...
kash73 Posted November 16, 2016 Author Report Share Posted November 16, 2016 Sorry, I had to get to my laptop to resize the image. Link to comment Share on other sites More sharing options...
Mark C. Posted November 17, 2016 Report Share Posted November 17, 2016 Did these cones ever get wet? That bubbled one looks weird Link to comment Share on other sites More sharing options...
kash73 Posted November 17, 2016 Author Report Share Posted November 17, 2016 Nope, the cones have never gotten wet. All three of the glaze cones (white ones) have the bubbles. I'm beginning to think my thermocouple might be bad, causing over firing. Something else that's been happening is a glaze that's supposed to be matte, has been coming out glossy and melting to my kiln shelves. So much so, that I have to buy new furniture. Link to comment Share on other sites More sharing options...
Mark C. Posted November 17, 2016 Report Share Posted November 17, 2016 Ok the white cones are not overfired much as the point is still almost equal to base. When you say the matts are shiny-that can mean you are firing them to hot. I can only see bubbles in that lower white cone but if they all are I'm suspect of that box of cone 6 cones. Matts go shiny when overfired. Put a cone near your thermocouple to test what that does next glaze fire Are the matts shiny on the top shelve where that top cone is bearly soft tip in the photo? Link to comment Share on other sites More sharing options...
Marcia Selsor Posted November 17, 2016 Report Share Posted November 17, 2016 I have seen that bubbling before. It is weird. But I wonder is there was a reaction to something near it in the kiln? Did it happen throughout the kiln? Â Marcia Link to comment Share on other sites More sharing options...
neilestrick Posted November 17, 2016 Report Share Posted November 17, 2016 Cooling rates can also affect matte/shiny results. There are many glazes that are shiny when cooled quicker, matte when cooled slower. Glazes can be runny and matte. It all depends on how they are achieving matteness. Link to comment Share on other sites More sharing options...
kash73 Posted November 17, 2016 Author Report Share Posted November 17, 2016 Marc C: Yes, the mattes turned shiny on all 3 shelves. I always place a cone close to the thermocouple, for every firing. Â Marcia: Yes, it happened throughout the kiln - all 3 shelves. I keep pieces at least 2" away from cones, which I try to vertically align with the thermocouple on each shelves. Â Neilstrick: I think you nay be onto something there as well, with the cooling rates. Â Thank you, everyone for your input to help me sleuth this! I'm running tests today and changing out my thermocouple - the tip is black and there appears to be some color change in the ceramic sleeve around it. Link to comment Share on other sites More sharing options...
neilestrick Posted November 17, 2016 Report Share Posted November 17, 2016 Is the thermocouple in a protection tube? It should be. Link to comment Share on other sites More sharing options...
kash73 Posted November 17, 2016 Author Report Share Posted November 17, 2016 It's in the ceramic "tube" that came with it - installed by a Skutt rep. I haven't removed it. Link to comment Share on other sites More sharing options...
neilestrick Posted November 17, 2016 Report Share Posted November 17, 2016 The thermocouple will blacken with use. You don't need to replace it unless it's ready inaccurately or it's looking really crispy and fried. Link to comment Share on other sites More sharing options...
kash73 Posted November 17, 2016 Author Report Share Posted November 17, 2016 its looking pretty crispy to me. What do you think? Link to comment Share on other sites More sharing options...
neilestrick Posted November 18, 2016 Report Share Posted November 18, 2016 It's getting there. Could probably go a few more firings. Link to comment Share on other sites More sharing options...
Mark C. Posted November 18, 2016 Report Share Posted November 18, 2016 These things are cheap-yours looks crispy and has a short life left. Link to comment Share on other sites More sharing options...
kash73 Posted November 18, 2016 Author Report Share Posted November 18, 2016 I keep a log and I've only done 26 firings. Is it normal for them to wear out so quickly? Link to comment Share on other sites More sharing options...
neilestrick Posted November 18, 2016 Report Share Posted November 18, 2016 26 is definitely too short. It will deform a lot more than that when it's dead. As long as there's not a crack in it it should go some more. When you said it's in a tube, is it one of THESE? These tubes help extend thermocouple life, and keep all that black stuff from flaking on your kiln and pots. Link to comment Share on other sites More sharing options...
kash73 Posted November 18, 2016 Author Report Share Posted November 18, 2016 No, I was just referring to the ceramic, segmented tube that it came with. Nothing that goes over the tip. Â I am going to run some diagnostic tests (if I can figure out how) and do a test fire. Everything I've read is leading me to believe it's over firing. Note: I haven't been doing any custom firing, only doing the programmed cone firing. Â I guess the fact that my bisque fires have been under and my glaze fires over, is what has me stumped. Link to comment Share on other sites More sharing options...
neilestrick Posted November 18, 2016 Report Share Posted November 18, 2016 I would start with new cones that aren't being weird and see if you get a different reading. But like Mark said, thermocouples are cheap so it wouldn't hurt to put a new one in, too. Link to comment Share on other sites More sharing options...
kash73 Posted November 18, 2016 Author Report Share Posted November 18, 2016 Replaced the thermocouple and running a visual test right now. Only the top and bottom elements are glowing. The test is at 370 degrees ramping to 500. Â Does this make sense? Link to comment Share on other sites More sharing options...
kash73 Posted November 18, 2016 Author Report Share Posted November 18, 2016 Here's a pic of the elements at 400 degrees Link to comment Share on other sites More sharing options...
neilestrick Posted November 18, 2016 Report Share Posted November 18, 2016 Skutt kilns have graded elements, meaning the very top and very bottom elements run hotter to compensate for heat loss out of the lid and floor. They will glow first. You'll probably have to run it up to 800 degrees before you see the middle elements glow. Link to comment Share on other sites More sharing options...
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