Recommended K Type Thermocouple, Please

[jonkzak]

All,

Could you please recommend a K type thermocouple?

My Story of Woe.
I've had a JDL612 PID for several years and it has performed very well, in other applications. I purchased an 800 C, type K TC on amazon, one of the generic ones. Connecting the TC to the PID just to measure the temp of the lead via the PID. Everything was working with low temps. The PID displayed proper values and was very stable. Once my lead was melted I inserted the TC about 25mm into the pool, all went well but temp was jumping all over the spectrum. I removed the TC and let it cool. I don't know if I got a bad TC to start but the second time I inserted it into the lead I started receiving errors on the PD saying max exceeded. Needless that was the end of that experiment. Now using that TC I get very erratic reading from the PID, even at room temp.

Well I'm not King Midas so the gold pot is not bottomless. Thus my request for input from you-all.

Could you recommend a vendor and model that you-all have had good experience with?

I also gather that you all immerse the TC several mm in the lead as most of the setups I have seen in the posts have static mounting of the TC, or am I incorrect in this assumption?

Thank you and Regards,

Jonkzak

[retread]

I use a long probe with the end about 1/2 inch from the bottom of the pot. Since it is a bottom pour I leave it in the pot. I have ordered them from different places, Amazon being one of them and have yet to run into a problem. I have 4 probes and they all work perfectly.

[JonB_in_Glencoe]

you mention, "I've had a JDL612 PID for several years and it has performed very well, in other applications." what TC were you using? did you change the parameters for use with the K type TC?
Here is a manual for the JDL612 that includes the instructions to set parameters.
http://fhupiora.fhupiora.home.pl/JLD612Manual.pdf

If you are aware of all that, and that isn't the issue, then you possibly got the incorrect TC. Hatch (our PID vendor sponsor) has mentioned ordering a batch of K type TCs and receiving the incorrect ones, I believe it has happened more than once.

[jonkzak]

Yes sir I double checked the setup parameters. As well I utilized a K type in the past, just the element was shorter and smaller well. Has anyone discovered what happens when you exceed the max temp rating on a K TC? I'm thinking that the 800 c rating was a bit liberal, but I don't know what that means a K type should be able to handle over 1000 c.

[jonkzak]

Thank you retread. I have had very good results in the past with Amazon...

[Mal Paso]

I had a $10 one from Amazon that worked at room temp and went nuts when I stuck it in lead. Sent it back. Got a good quality one from Amazon for a lot more money.

Anyone know a good, cheap one for lead that reaches the bottom of the pot?

[Mike W1]

I had a $10 one from Amazon that worked at room temp and went nuts when I stuck it in lead. Sent it back. Got a good quality one from Amazon for a lot more money.

Anyone know a good, cheap one for lead that reaches the bottom of the pot?

I've got some cheap ones but my original 6" TC's from Auber were around $19@ and still working fine. Probably money well spent I think.

[jonkzak]

I just took delivery of one cost $9.36. I haven't tried it but if the size is an indication this should work. It is beefy and 8" long.

https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

Description says good to 1300 C.

Regards,

Jonkzak

[Mal Paso]

Yep! That's the exact model I Sent Back.

This is what I bought. https://www.amazon.com/gp/product/B0...?ie=UTF8&psc=1

[Mal Paso]

I've got some cheap ones but my original 6" TC's from Auber were around $19@ and still working fine. Probably money well spent I think.

I wish they still sold those. The current 6" high temp have a 3" section limited to 400 degrees.

[Walter Laich]

I like 4" length K-probes as this allows them to get close to the bottom of the pot without having a the top stick too far out of the top.

I take a section of 12 ga wire and wind it around the probe the mount it to the pot. this mounting gives me be ability to adjust the angle of the probe a it while keeping the center of the pot clear

[dikman]

I've bought 3 x 4" off ebay (from China, of course) dirt cheap and other than fitting a connector to the cable they're still working fine. I always keep a spare, just in case.

[CGT80]

I used a 6" from auberins with my lee 20 and it worked for a number of years and then got sporadic. I had to get the 10" version so it would reach the bottom of my new pot, and it is just long enough to extend above the top of the pot. I have been running the pot only filled half way, so I can' t say what will happen if I fill it up. They aren't cheap, but seem to work well. I also got the one with a ring terminal to use in the powder coating oven.

I don't remember seeing it being limited to 3" inserted when I bought the last one. Also, 400 degrees C not F. That is 750F, according to the description. That is in the mid to upper end of the temps I have used.

[wjham77]

+1 ebay/china thermocouples, cheapest option, the more expensive ones resold in the states are made in china too.
you can buy 2-3 for the price of one.

[kbstenberg]

If I could change course a little. I have the Aubers K Type probe. The wires go directly from the probe to the controller. If I get a new probe could I use several inches of my present probes wires. And put some kind of disconnect. So I don't have to have the probe hooked continually to my PID? I remember something about only using a specific type of wire.
I am electrically challenged. So please write slow and loudly.

[Mike W1]

If I could change course a little. I have the Aubers K Type probe. The wires go directly from the probe to the controller. If I get a new probe could I use several inches of my present probes wires. And put some kind of disconnect. So I don't have to have the probe hooked continually to my PID? I remember something about only using a specific type of wire.
I am electrically challenged. So please write slow and loudly.

Yes you can use a piece of your wire from the TC you have. You want a panel jack that's made for K type also. Will try and stick a picture in.

[JonB_in_Glencoe]

If I could change course a little. I have the Aubers K Type probe. The wires go directly from the probe to the controller. If I get a new probe could I use several inches of my present probes wires. And put some kind of disconnect. So I don't have to have the probe hooked continually to my PID? I remember something about only using a specific type of wire.
I am electrically challenged. So please write slow and loudly.

it's always best to connect a TC directly to a PID. Any other connection/slice will effect the signal. But when it's necessary, using the proper disconnect would minimize that effect...also, for our purposes, any small effect doesn't really matter.

https://www.auberins.com/index.php?m...roducts_id=119

edit: looks like I type too slow, LOL.

[popper]

The TC is good to high temp but the wire insulation often is NOT. They also have a tendency to break the wire to give you the intermittent reading. Replaced my Auber one with a high $ one from omega, good so far. The wire used is not meant to be bent a lot.

[dikman]

...also, for our purposes, any small effect doesn't really matter.

I've been saying that for a while as we aren't striving for laboratory precision in what we do. I've been using BNC co-ax connectors ('cos that's what I have handy) and they've been working fine.

[Greg S]

I had the same problem on mine with reading fluctuating. Turned out the wires on the male plug were shorting on one another. Took the male plug apart and rehooked the leads better and problem gone.

As far as hooking up, i used standard copper 18ga from the female plug to the PID connections. The thing is it needs to be the same type and length per lead.