what to do with a little to long thermocouple for the kiln?

Daniel Rohde

Daniel Rohde

Knifemaker / Craftsman / Service Provider
Joined
Jul 22, 2014
Messages
1,050
Hey Guys!
I was going to finish up my kiln tommorrow and I was getting the thermocouple in http://www.auberins.com/index.php?main_page=product_info&cPath=20_3&products_id=39 and I don't need the 6" I have I only need about three or four and I don't want 3" of thermo couple sticking out of the top. I was wondering could I bend it or cut it without losing any accuracy?
also can I slide the top two,or just one, ceramic separators? because those would be in the kiln.
https://lh3.googleusercontent.com/-...0gzI_HA/w1113-h835-no/IMG_20141205_211807.jpg
Thanks
DR....
 
Thermocouples operate off of voltage, so you could cut it but honestly I don't see why you would worry about it. Either bend it or run with it straight. A few extra inches won't hurt anything and if for some reason you decide you need a bit longer it is much harder to add than take away. And for a bit of unsolicited advice I would ditch the auber thermocouple and get an Omega. Either Inconel or OmegacladXL. This is one area where you want the experts to build your reading instrument. The few extra bucks you spend will give you a much better certainty of accuracy seeing as it comes from a company that builds industrial processing equipment as opposed to smoking equipment. A 4" OmegacladXL thermocouple with a "rugged transition joint" will cost you the same as the auber version and I can promise that it will last longer and have a higher degree of accuracy than that of the auber. I often see people complaining of their instruments not being as accurate as some of us claim they can be only to find out they use ebay or some other off brand thermocouples in their setups. When it comes to the business end, always buy the best if you want the best accuracy.
 
All good advice.

I always recommend using the most robust thermocouple you can get.... 8-10 gauge or 1/8" is what you want. As Matthew pointed out, the one thing that really determines how well your system works is the thermocouple. This is not the item to save a few bucks on. Mount it on a TC block, too. Wire nuts and other connectors aren't what you want. Use ONLY TC wire rated for the TC type. On that TC you will need to connect it to the PID with type K TC wire, making sure to match polarity. This will make the reading more accurate. If you don't have some, and can't easily get a piece, send me an email or PM and I'll roll up a length and stick it in a mailer for you.
 
Thanks Guys!
I did come with specific K type thermocouple wire so I won't need any. It also came with a ceramic terminal block that the TC mounts to is that what you meant by"mount on a TC block"? Thanks guys I hope to wire it up today.
Thanks for the help
DR....
 
Daniel, I'm not sure what is meant by "Inconel or OmegacladXL" TC - this has to refer to the covering, NOT the TC wire itself. A type K (which you require) TC will have one wire of chromel , and one wire of alumel alloys. As Stacy says, since you require a large (#8 to #10 gauge) wire, the high temp will require the ceramic insulators, the accuracy of the Auber TC will be as good as any other well made type K. Type K are not known for high accuracy, but is used because of it's because of it's ability to handle high temperature.

Yes, the ceramic terminal block is what Stacy was referring to - use for connecting the TC to the TC wire, being sure to keep the polarity matched. Yes, feel free to remove a ceramic insulator and bend (or cut) the TC wire you you please, it's 90% (positive) and a 95% (negative) nickel alloy wire.

Here's a good bit of reading on type K TC: http://en.wikipedia.org/wiki/Thermocouple#Type_K

Ken H>
 
Ken H> said:
Daniel, I'm not sure what is meant by "Inconel or OmegacladXL" TC - this has to refer to the covering, NOT the TC wire itself. A type K (which you require) TC will have one wire of chromel , and one wire of alumel alloys. As Stacy says, since you require a large (#8 to #10 gauge) wire, the high temp will require the ceramic insulators, the accuracy of the Auber TC will be as good as any other well made type K. Type K are not known for high accuracy, but is used because of it's because of it's ability to handle high temperature.

Yes, the ceramic terminal block is what Stacy was referring to - use for connecting the TC to the TC wire, being sure to keep the polarity matched. Yes, feel free to remove a ceramic insulator and bend (or cut) the TC wire you you please, it's 90% (positive) and a 95% (negative) nickel alloy wire.

Here's a good bit of reading on type K TC: http://en.wikipedia.org/wiki/Thermocouple#Type_K

Ken H>
Click to expand...

You are right Ken the Inconel and OmegaCladXL are sheathings. They will allow the thermocouple to last much longer in the high heat environment. The Omegaclad has also been shown to improve the deviation of the reading at elevated temperatures. However not all type K are created equal. Omega actually uses proprietary alloys for their wires that provide better accuracy over the range of thermocouple's measurement. So the accuracy of the Auber TC will not be "as good" as any other well made type K. Auber also doesn't provide any technical documentation for them, nor the country or company of origin. Omega is a sure bet and it will last longer in any environment and has a guarantee of accuracy for only a few dollars more. Why skimp less than $10 on the most critical part of the system?
 
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