Emma Hendler on tue 8 feb 00
Does anyone have experience with the following problem? I am trying to
troubleshoot a firing problem with my L&L JD230 kiln. It is the model
with the Dynatrol automatic controller. While the kiln is 2 years old,
it hasn't been fired many times (4 cone 06 bisques, 5 cone 6 glazes).
I've tried the following schedule (posted by Jan Walker on Feb '97).
The kiln seemed to move along according to schedule until about 1000C,
at which point it took 7 hours to get to 1200C. During the last two
hours, it moved 5 degress. After 21 hours, the cones bent at 1200,
and I skipped to the ramp down segment. After six hours ramping down,
the kiln was still at 800C. Does this sound like a physical problem
with the kiln, or a controller problem?
Glaze (^6 roughly) Degress Centrigrade
ramp set hold (minutes)
50 120 60 just be sure all steam etc is out
150 525 0
75 600 0 through quartz inversion point
150 1000 0 organics are gone already
50 1205 90 slowwwww, skip out of the soak when cones look
right
150 900 0 control drop to let craters heal
50 700 0 control drop to let crystalline depth develop
Thanks for any advice.
Emma Hendler
ehendler@att.worldnet.att
amy parker on wed 9 feb 00
Emma - I've been using Janet's schedule for my Olympic 1023H since about
this same time...
At 50/hr from "room temp", say 20 C, 2 hours to 120, plus 1 hr hold. 3 hrs
@150 to 525 2.75 hrs + 3 = 5.75 hrs so far.
@75 to 600 1 hr + 5.75 = 6.75
@150 to 1000 = 2 2/3, call it 2.75 + 6.75 = 9.5 so far
@ 50 up to 1205, about 4 hrs, should be about 13.5 hours
plus the soak for 1.5 hours, should be about 15 hours to this point.
The cool down would take about 6 hours for the schedule from 1205 to 900 @
150/hr would be 2 hours, then 4 hours @ 50/hr to drop from 900 to 700, the 6
hours you describe.
Sounds like your kiln "stalls" after 1000 C is reached. Once it finally
achieves the desired temp, it is able to maintain the cooling rate that you
have programmed. With my kiln/controller combination, I had to set top temp
to 1180 for cone 6, and I changed the program to go to 1130 at 150C/hr, then
slow down the last hour to sneak up on the cone..."worked for me".
I'm guessing here, but sounds like you are running out of "juice" at the top
temp - did all your other ^6 firings take this long too? Does the kiln
continue to cycle (mine obviously sends full power intermittently - makes
loud clicks) on/off after you hit 1000 or is it steady "on"? Are you sure
that you have the correct gauge of wire for the amperage and distance from
the box to your kiln? If you are running at the distance limit for your
recommended wire size, this could cause the problem you describe, and could
also be overheating the wires, causing a potential fire hazard. Since your
kiln is so new, please do have this variable checked carefully be a licensed
electrician. Sounds like the controller is working correctly, just not
getting the cooperation it needs from the kiln.
Amy
--------------original mail: ---------------
>I've tried the following schedule (posted by Jan Walker on Feb '97).
>The kiln seemed to move along according to schedule until about 1000C,
>at which point it took 7 hours to get to 1200C. During the last two
>hours, it moved 5 degress. After 21 hours, the cones bent at 1200,
>and I skipped to the ramp down segment. After six hours ramping down,
>the kiln was still at 800C. Does this sound like a physical problem
>with the kiln, or a controller problem?
>
>Glaze (^6 roughly) Degress Centrigrade
> ramp set hold (minutes)
> 50 120 60 just be sure all steam etc is out
> 150 525 0
> 75 600 0 through quartz inversion point
> 150 1000 0 organics are gone already
> 50 1205 90 slowwwww, skip out of the soak when cones look
>right
> 150 900 0 control drop to let craters heal
> 50 700 0 control drop to let crystalline depth develop
>
>Thanks for any advice.
>
>Emma Hendler
>ehendler@att.worldnet.att
>
>
amy parker Lithonia, GA
amyp@sd-software.com
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