How to install a cheap 1/4-20 TC probe?

So I got my cheap Sestos PID coming and started looking at mounting the probe. To make it universal between my keggles I was going to mount it on the pump outlet and whirlpool back into the HLT, recirc to the MLT, and whirlpool the BK at the end of the boil (using the PID to just monitor the temp).
Then I saw the cheap 1/4-20 thread thermocouples that come free with the PID have the anoying "back nut" arangment, i.e. the TC probe is sitting loose in the nut and will no be liquid tight at all
I have seen some use JB weld to seal the TC probe, has anyone done something else?
I was thinking maybe tap the side of a socket to accept a bolt and then tap the bolt for the TC probe, or just tap the socket to just before it breaks through. Just don't know how much this would cause the temp to lag due to the socket needing to heat up first.
Anyone got any other suggestions?

mattd2 said:

So I got my cheap Sestos PID coming and started looking at mounting the probe. To make it universal between my keggles I was going to mount it on the pump outlet and whirlpool back into the HLT, recirc to the MLT, and whirlpool the BK at the end of the boil (using the PID to just monitor the temp).
Then I saw the cheap 1/4-20 thread thermocouples that come free with the PID have the anoying "back nut" arangment, i.e. the TC probe is sitting loose in the nut and will no be liquid tight at all
I have seen some use JB weld to seal the TC probe, has anyone done something else?
I was thinking maybe tap the side of a socket to accept a bolt and then tap the bolt for the TC probe, or just tap the socket to just before it breaks through. Just don't know how much this would cause the temp to lag due to the socket needing to heat up first.
Anyone got any other suggestions?

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Do you have an o-ring on it? Add washes as needed to use up the extra grip length of the threads.

EZ fix get the 2" RTD Sensor from Auberins

Problem Solved!

Side Note: What do yo think about the Sestos PID?

if your probe is 1/4" OD like most are, you can get a 1/4" compression to 1/4" MPT fitting

use a metal compression insert if you want the probe to perminantly be attached to the fitting, or a plastic compression insert if you want it to be removable.

small pic, but like these

jose4030 said:

EZ fix get the 2" RTD Sensor from Auberins

Problem Solved!

Side Note: What do yo think about the Sestos PID?

Click to expand...

Only issue is I want to mount it on the pump outlet so 2" will be too long, and I want to go TC becuase, as I have heard, they are faster at responding to temp changes.
Just to clear up what the 1/4-20 threaded TC looks like I drew the picture belwo in in MSpaint and this is from the internet
.
I was thinking maybe if I heated up the gap between the thread and probe and soldered them together it might work... might

Food grade silicone? Just stabbing in the dark here.

I think a copper/brass threaded plug with a center hole drilled and threaded, would work.

I asked about the PID because I ordered the same one a was just wondering if it worked for you.

jose4030 said:

I think a copper/brass threaded plug with a center hole drilled and threaded, would work.

I asked about the PID because I ordered the same one a was just wondering if it worked for you.

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Sorry, just realise I didn't answer that one. I haven't recieved the PID yet either but the thread on here made it look promising.
https://www.homebrewtalk.com/f51/sestos-pid-temperature-controllers-d1s-vr-220-a-203939/

Food grade (?) silicon sealant would be and idea, or some expoxy resin. Or might just have to go the bolt way.
I just don't understand what these probes a useful for without modifying them, you would think any probe that you screw into something would need to be sealed.

Does it thread into a flared pipe style fitting like a brakeline? If so that might give you a water tight connection.

mattd2 said:

you would think any probe that you screw into something would need to be sealed.

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not everything needs to be air/liquid tight. furnaces, ovens, heaters, etc... for liquid, a thermowell is almost always used.

the speed difference between thermocouples and RTDs is insignificant in this application. dont let that be the deciding factor. if you can more easily mount a RTD (without using methods normally frowned upon by engineering folk, like epoxy/caulk/sealant), do that.

I will be following POL's approach..

see:

https://www.homebrewtalk.com/f11/bling-bling-electric-herms-conversion-93217/#post1025200

Except im just going with a standard SS 1/4-20 nut from lowes vs the wingnut he used. and 2 stainless washers with an oring on the inside of the keggle.

audger said:

not everything needs to be air/liquid tight. furnaces, ovens, heaters, etc... for liquid, a thermowell is almost always used.

the speed difference between thermocouples and RTDs is insignificant in this application. dont let that be the deciding factor. if you can more easily mount a RTD (without using methods normally frowned upon by engineering folk, like epoxy/caulk/sealant), do that.

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Fair enough about not everything needs to be liquid/gas tight but I still wouldn't be keen to have hot gas leaking out of my furnace
Another question is (hopefully I get home tonight and my PID has arrived and I can answer myself ) is the nut loose on the probe, i.e. can it slide all the way back on the wire to the crimped connectors, or is it stopped from sliding to far back (that picture I posted looks like it the probe might be crimped just out of the "bolt")? Edit#2: Just got a call from the wife that the PID has arrived!

aquenne said:

I will be following POL's approach..

see:

https://www.homebrewtalk.com/f11/bling-bling-electric-herms-conversion-93217/#post1025200

Except im just going with a standard SS 1/4-20 nut from lowes vs the wingnut he used. and 2 stainless washers with an oring on the inside of the keggle.

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Yeah POL's approach was what I referenced in the first post, and seems like the only way to do it without a using/making a thermowell. I was hoping to have a bit more finesse to the probe than a lump of JB weld which is why I thought silver solder, but I don't want to spend $50+ on a roll of solder to use $0.50 worht of it
Also Audger, why would you say epoxy is forwned upon? Seemed like a good idea to me (as long as I didn't cover the whole probe in the stuff).
Edit: Ok no epoxy as they satrt to get soft at 100°C , not 100% keen on silicon sealant so maybe try get a small amout of silver solder for cheap.

Found some more info on soldering SS, and found some places that will sell 10g tubes of solder for pretty reasonable so I will be soldering my probe. I'll be sure to update once it is done

mattd2 said:

...Another question is (hopefully I get home tonight and my PID has arrived and I can answer myself ) is the nut loose on the probe, i.e. can it slide all the way back on the wire to the crimped connectors, or is it stopped from sliding to far back (that picture I posted looks like it the probe might be crimped just out of the "bolt")? Edit#2: Just got a call from the wife that the PID has arrived!...

Click to expand...

OK to answer my own question: No the bolt is not loose on the probe wire, The probe has been inserted through the bolt and then crimped to stop the bolt slidding back out.

mattd2 said:

Edit: Ok no epoxy as they satrt to get soft at 100°C , not 100% keen on silicon sealant so maybe try get a small amout of silver solder for cheap.

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From http://jbweld.net/products/jbweld.php

"Like metal, J-B WELD can be formed, drilled, ground, tapped, machined, filled, sanded, and painted. It stays pliable for about 30 minutes after mixing, sets in 4-6 hours, and cures fully in 15-24 hours. It's water-proof; petroleum-, chemical-, and acid-resistent; resists shock, vibration, and extreme temperature fluctuations, and withstands temperatures up to 500° F. J-B WELD is super strong, non-toxic, and safe to use. Before it sets, you can clean up with soap and water."

If it starts getting soft at 100degC, id be suspect to its claim to withstand temp's up to 500degF.

Do you have real world experience with this?

aquenne said:

...If it starts getting soft at 100degC, id be suspect to its claim to withstand temp's up to 500degF.

Do you have real world experience with this?

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Yeah, the epoxy I was refering to was stuff made by araldite/selleys (sp?). It said that the normal stuff (their version of JB weld) was not good for applications under water, it was water resistant but still pourous. They had a "aqua" epoxy that was good underwater but the max continuos temp was something around 80 °C.

Have you a datasheet for JB weld because all I could find was their promotional material/statments on the website, saying it is good to 500 °F and that it is water resistant isn't really the same as saying it is ok to use underwater at 500 °F (or even 212 °F).

mattd2 said:

Found some more info on soldering SS, and found some places that will sell 10g tubes of solder for pretty reasonable so I will be soldering my probe. I'll be sure to update once it is done

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Ok this was the info I found earlier http://www.jm-metaljoining.com/pdfs-uploaded/Joining Stainless Steel.pdf

Soldered my TC last night with some tin-copper (?) (no silver) solder, and it seems sealed now. Had to buy a small butane gas torch as the 40W iron would not cut it heating up the bolt. Need to clean it up a bit as it is a bit blobby in one spot but should be sealed now.
Will post a photo later tonight.

Try some Teflon tape on the threads. It costs like a buck at lowes. just go around the threads a couple more times then usual. That way it's not as permanent as jb weld or soldering and no chance of contamination because you can always pull it out clean it put a bit more teflon on and put it back in. Hope that makes sense I've had a couple beers

I think you missed the point SS. I am not trying to seal the threads, the issue is the threaded bolt has a hole that the TC is slide through. This hole is where the leak will occur.

Ok sorry. I understand now. Could you just weld the front of it? With a tig welder? If you can get it hot enough to solder I would imagine you could just weld it. It would literally take 5 seconds.

SS_Brewing_Co said:

...It would literally take 5 seconds.

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And a welder
Yeah you could but soldering is easier and works (hopefully)

Oh yeah sorry. I guess you would need a weldor. Well if I did t cost an arm and a leg to ship stuff I would weld the sh*t out of it for you. Sorry I just assume everyone welds or know someone that does. I just don't like the soldering idea for chance of contamination.

SS_Brewing_Co said:

Oh yeah sorry. I guess you would need a weldor. Well if I did t cost an arm and a leg to ship stuff I would weld the sh*t out of it for you. Sorry I just assume everyone welds or know someone that does. I just don't like the soldering idea for chance of contamination.

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Yeah, i though the lead free solder would be ok and it will be exposed to boiling water/wort so should kill anything that could harm the beer each time it is used.
I actually do know a welder (a whole shop full of them) but I got a whole lot of other stuff I want/need done so don't want to use up my favours on stuff I can sort myself

Yeah I understand that. I see you are form new Zealand. Might the welding shop you know be Teckno pak?

SS_Brewing_Co said:

Yeah I understand that. I see you are form new Zealand. Might the welding shop you know be Teckno pak?

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No, but I think one of the other contractors that has done a lot of work on one of the sites in Timaru I was involved in has worked with them, the name sounds familiar How do you know them?

I'm a contractor out at land o lakes in California and they put a bunch of equipment in and I helped them out

So I actually got back to this. I had soldered up the TC as discribed above a fair few months ago but was having difficulties on how to actually mount the TC in the pipe. My original plan was to drill and tap a barrel nipple and thread it in with an o-ring or teflon tap to seal. Long story short I didn't have access to a 1/4-20 UNC tap. I have my FIL over this weekend to show him a brew-night so I wanted this to be done, I ended up drilling the nipple and then soldering the TC in place.
Took a few goes to get the right technique but I have trialed it and it held water! Ended up holding the nipple in a vice (hole on top), sitting the TC in the hole, then heating the nipple from the inside and applying solder to the joint from the outside. I will try and get some photos up some time soon.

Cheers guys

OK photo update:
TC soldered into nipple and the pump setup
Cheers