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GlassDoc 2020-06-13 6:34pm

Kiln is too hot
dug out the kiln. JenKen cube-4.
It ran too hot. rods across kiln furniture would sag.
Called JK, got new change.
So now trying to just reset to the new temp.
Any tips for getting the temp right? I've got it set for 860 now as my "new" annealing temp. a 5" soft glass rod will still sag about 1mm when bridging across 2 supports.

any pointers? Anyone had this issue ever?

Laser pointer temperature gun has lots of variation and the temp drops quick when door opens, so not too accurate.

I've been having fun looking for a post answer here but getting lost/distracted in this vast forum.
peace to all.


KJohn 2020-06-13 9:47pm

Hi Ed!
I just had the same exact problem with my kiln. I just reset the temp a bit lower, but I know it's not exact. The temp for slumping the rods starts at about 1000F, if that far that's what I've read anyway. What is your info?

I've got mine set at 875, as it was running at least 50 degrees too hot. I'm checking to see if my rods are slumping. They should not slump at all if the kiln is holding the right temperature. Some folks say to use kiln cones, I haven't tried that yet.
Post updates if you want, good luck

Eileen 2020-06-14 7:43am

Is that Fahrenheit? Can you find a pyrometer you can stick the tip in there to verify?

GlassDoc 2020-06-14 12:09pm

Thanks for the thoughts Eileen and KJohn.
I think I'm going to have to bite the bullet and buy a pyrometer. So many gizmo's to fix my gizmo's researched and owned already. I'll share what I learn.

I just hope it's running stable and not all spikey and unmanageable.


Speedslug 2020-06-14 2:27pm

You mentioned that you "dug the kiln out", did you make sure that nothing made a home inside the controler?

Small critters are really fond of finding small spots to live in and if they managed to cross a few of the electronic parts on the circuit board with webbing or their own bodies it can radically change they way the controller functions and won't always trip a circuit breaker or blow a fuse.

I know there are red ants that simply love the area around live switches and I have had brown ants attracted to some of the soldering flux left on circuit boards when they leave the factory.

My other thought is to wonder what kind of glass rod you are using in your 'sag test'.
Soft glass in white will melt if you just look at hard for a few minutes while most of the transparent blues I play with need some serious persuasion in the torch flame to get it to flow and even then it will stiffen up if you take your eye off it for a second.

Good luck with finding a fix.

Oh and look for screw contacts getting oxidized after a long time in storage.
I take the screws out and rub them with a pencil eraser to clean off the invisible oxidation layer on the leads and the screw pads if I'm chasing down funky symptoms while troubleshooting electronic systems.

Shadooba 2020-06-20 9:12am

960 is the temp for boro i even run it hotter like 1080

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