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-   -   Aim Kiln Keeps Melting my Glass (http://www.lampworketc.com/forums/showthread.php?t=308010)

Scochoman 2018-10-22 3:50pm

Aim Kiln Keeps Melting my Glass
 
I recently got a Aim 84BD kiln , used, and am having problems with my finished projects sagging and becoming deformed during annealing. My pyrometer shows temps around 1000F but is still causing things to deform and flatten. Am wondering if it is the firing rate maybe or ?? Any advise would be helpful, thanks.

hyperT 2018-10-22 9:53pm

Pyrometer
 
You need to go to a ceramics store and get some ceramic cones, cone 022 should work. The people there can help you on how to set them up in your kiln.
Cones bend at a very specific temperature. You can then adjust your pyrometer to that setting. There should be a screw on it to adjust the dial on the pyromter to that temperature.
You can also look up, "How to adjust a Pyrometer"

Annealing Point, Bending Point, Melting Point as you can see the Bending and Melting Points are much higher than the Annealing Point.
Typical Soft Glass Annealing Point is 950. Bending Point is around 1300 Melting is above 1500. Looks like yours is reading off about 400 hundred degrees.
Don't take it up so high til you can fix it. They are somewhat delicate instruments, maybe it took a bump in transportation.

Have fun, Wayne

Scochoman 2018-10-23 1:29pm

Thanks, was wondering if that was the case as well , with it not reading correctly. Will try your advice with a cone and see what I can figure out.

hyperT 2018-10-24 3:35pm

Quote:

Originally Posted by Scochoman (Post 5011844)
Thanks, was wondering if that was the case as well , with it not reading correctly. Will try your advice with a cone and see what I can figure out.

You're gonna need 3 cones stuck in some mud to do the calibration ask the ceramics shop or a local Potter.
A pottery person my even calibrate it for you?

Speedslug 2018-10-24 5:24pm

I hope this doesn't seem to far off base but is there any possibility that the kiln is displaying celsius and you are looking for fahrenheit?

1000 C is equal to 1832 F after all and that would make puddles pretty dependably.

Scochoman 2018-10-27 10:43am

It is definitely in Fahrenheit. It is a older pyrometer in a case, Johnstone ? I believe. It has a ceramic thermocoupler that I insert through the peephole. I got some cones, Orton 022, and the way I did it was I fired the kiln fully on til the pyrometer read 950, i then dialed the firing rate back to hold the temp and let it sit for a while to even out. I then inserted a cone and within a few minutes it was a blob. So I dialed the firing rate way down til it was sitting at 700. I slowly raised the firing rate like every thirty minutes until the cone started to bend. The sweet spot I found was a lower firing rate with the pyrometer reading around 820F... So hopefully I have it figured out and maybe it's just the firing rate ?? . Also this is my first time using cones so not sure if my method is accurate but I would think if bending temp is around 1060F on the cone, as long as my temp was staying constant it shouldn't matter.

hyperT 2018-10-27 1:19pm

Adjustment
 
There should be a way to adjust or calibrate the pyrometer. On mine there is a screw just under the dial window. By turning the screw left or right you can move the dial indicator up or down.

hyperT 2018-10-27 1:40pm

Pryrometer
 
If it's not there I don't know what to tell you?


Speedslug 2018-10-28 8:14am

Also look out for loose, dirty or corroded wire connections.

These things are electrical indicators after all and wires twisted together with bare fingers a decade back will slowly creep up in resistance and that will give you false readings eventually.


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