L&L BLOG

Do new thermocouples need to "broken in"?

I expect to receive delivery tomorrow evening of 3 new thermocouples for my JD-2927-HD kiln (originally purchased in 2007). Should I plan a "run-in" firing, say to Cone 5, when these new thermocouples are installed? (Note: I installed new elements last October and performed a "run-in" firing for the new elements.) Thank you. -- Thomas ************** Thomas -

No need to "break in" your new thermocouples. On the other hand, elements need to be "broken in" to eliminate the stretch springiness and oxidize them for protection. None of this applied to thermocouples.

One thing to watch out for, however, is that your old thermocouples may have drifted in accuracy over time. If you changed your thermocouple offset you may want to reset it to the original value - which would have have been +18 Deg F if you have our ceramic protection tubes.

L&L Kiln Mfg., Inc.


Unbalanced 3 Phase kilns and why the amperage can be odd

A distributor asks:

On 208V 3P, why does the e23S-3 pull 34.6 amps, but the e23T-3 only pulls 27.7 amps? Is that a typo, or does it have something to do with splitting 3 phase over 4 elements?

Answer: On an e23T-3 you have three balanced circuits. There is a total of 48 amps being split three ways. A simple way to calculate this is that each phase is taking 16 amps X the 3-phase factor of 1.732 to get 27.7 amps on each phase. On the e23S-3 the full amperage of 40 amps is split between two phases with one phase unused. So 20 X 1.732 = 34.64 per phase. You take the highest amperage on any phase to get the amperage of the device.


Chris Corson device for lifting his lid off the kiln for loading sculpture

Here an image of the pulley system I rigged to lift my kiln's lid out of the way.  The parts came from Home Depot and Tractor Supply.  My wife helps me with the rings.  I just use the pulley system for the lid -- so it gets lifted up and suspended out of the way while I deal with the rings.

Device to pull kiln apart
Device to pull kiln apart

My work is figurative sculpture, mostly standing torsos and seated figures.  You can see them at www.chriscorsonsculpture.com.  My standing figures are why I bought the Pull-Apart.  I needed interior height and a safe way to get bone dry pieces in place.  The Pull-Apart system makes it easy.

I've attached an image of a piece I completed yesterday (28" tall).  Still green, it will be the next thing to go in the kiln.

Sculpture
Recently completed work

Christopher Corson

NOTE FROM L&L: Here is a link to the PULL-APART Jupiter kilns mentioned in this post.