NawaeClay Posted June 7, 2017 Report Share Posted June 7, 2017 Today I decided to test fire a used Paragon TnF-66 kiln I ended up with. I didn't put any of my work in it, just ^06 Pyrometric cones throughout and set the Sentry 4.0 12 key controller to this program: Cone 06 (bisque test) Fast (for testing) No preheat No hold (was planning on a 10min hold for a real bisque) No cooldown (plan to -140F a hour for real bisque) I kept a steady watch over it and logged the temperature and took notes every 30 minutes until the program completes and stopped. (I have a photo if needed) The program completes at 8:08pm @ 1827F HOWEVER when I crouched down to hit the "Stop" button 3 minutes later the readout tells me it was 1683F and dropping (because the program stopped obviously). The dropping didn't concern me, the -144F over 3 minutes did. Is that normal or could it be because I didn't have my peepholes covered? Sorry, but is all new ground for me as I've never fired anything before and I am learning through all info I can find - books and net, so ANY advice is appreciated. Much Thanks, M.Wooster Link to comment Share on other sites More sharing options...
Marcia Selsor Posted June 7, 2017 Report Share Posted June 7, 2017 I'd say an empty kiln could drop that fast. More mass inside would slow it down. It also slows down as it gets lower in temperature. Marcia Link to comment Share on other sites More sharing options...
Tim Allen Posted June 7, 2017 Report Share Posted June 7, 2017 If you were to continue monitoring the temperature every 30 minutes during the cooling phase, and then graph your data, it would probably look something like this: Marcia's right on about the lack of thermal mass having a significant role in your case. Also, just in general, smaller kilns will cool more quickly than larger kilns, because the smaller kiln will have a larger surface area to volume (mass) ratio -- cooling is primarily due to radiative and conductive/convective heat losses to the air at the outside surface of the kiln. Leaving the peep holes open will facilitate convection of air through the kiln interior (somewhat), but that will have only a marginal impact on the overall cooling rate, because peep holes tend to be small. Still, if you want slow cooling, leave the peep holes closed. (Leaving the damper and burner ports open on a fuel-fired kiln will have a larger impact on the cooling rate, because those openings are typically much larger.) Link to comment Share on other sites More sharing options...
neilestrick Posted June 7, 2017 Report Share Posted June 7, 2017 Yep, they drop like a rock at first. Link to comment Share on other sites More sharing options...
Min Posted June 7, 2017 Report Share Posted June 7, 2017 "No cooldown (plan to -140F a hour for real bisque)" - don't need to do a slow cool for a bisque, just let it go off after reaching top temp and cool down on it's own. Welcome to the forums. Link to comment Share on other sites More sharing options...
NawaeClay Posted June 7, 2017 Author Report Share Posted June 7, 2017 Thank you all for the replies, I made a trip into Houston today to snag some plugs and decided to do an actual bisque load today just to try. Today's run is pretty much the same as yesyerday, except Medium speed, plugged holes at 1000F, hold for 10 mins (wasn't 100% if I should have held for bisque or not), and then no cooldown. I have maybe 3 more hours or so until the program completes so fingers crossed. I DID have 1 last question regarding my cones from yesterday. I also have a photo of them IF needed. Top shelf - perfect bend Middle Shelf - slight bend Kiln Floor - over bent, but not much Could this be from not plugging the holes, being empty, and/or firing fast or a possible coil issue? ALL coils lit up glowing orange so I was a bit confused. Thank you in advance, Meagan 😊 Link to comment Share on other sites More sharing options...
Guest Posted June 7, 2017 Report Share Posted June 7, 2017 Different places in the kiln will have different temperatures. How close the pot/cone is to the elements will make a difference. Its not usual for the top of the kiln to be hotter than the bottom Link to comment Share on other sites More sharing options...
neilestrick Posted June 8, 2017 Report Share Posted June 8, 2017 When you're firing work, plug all the peep holes except the top for the entire firing. No need to mess with leaving them open at first. But you need the top one open the entire firing to allow fumes to escape. This is assuming you don't have a downdraft vent on the kiln. If you do have a downdraft, then you need to keep all the peeps plugged all the time. Link to comment Share on other sites More sharing options...
NawaeClay Posted June 9, 2017 Author Report Share Posted June 9, 2017 Thank you all for the responses, I was able to complete a successful bisque batch Wednesday and when I opened the kiln Thursday morning everything was pretty much perfect. No explosions, no cracking, not a lot of shrinkage, and the only thing that seemed off was all of my ^06 cones gave me a reading of about ^05. Other than that, they were all the same bend for the most part and everything seemed to come out nice and "bisqued". :-) Link to comment Share on other sites More sharing options...
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