Temperature Probes & Moisture

[BuyLowSellHigh]

The issue of moisture in temp probes and killing the probe keeps coming up.  Had a thought -- drawing from my marine electrical experience -- has anyone tried heat shrink non-stick tubing as a seal at the probe opening where the cable goes in?  The common PTFE (e.g., non-stick) has a continuous use temp of 500 F (260C).  There are materials that can take higher, but for Bradley use I would think that would do it.

[NePaSmoKer]

The issue of moisture in temp probes and killing the probe keeps coming up.  Had a thought -- drawing from my marine electrical experience -- has anyone tried heat shrink non-stick tubing as a seal at the probe opening where the cable goes in?  The common PTFE (e.g., non-stick) has a continuous use temp of 500 F (260C).  There are materials that can take higher, but for Bradley use I would think that would do it.

Done that.

Heat rated shrink tube from my USAF working days..... No luck

FYI.....For all

Only the tip of the probe does the readings, not the entire length of the probe.

[BuyLowSellHigh]

Thanks, NePaS,  Kind of figured it was too easy, cheap and obvious to not have been tried   ;D

I suspect part of the problem is the extreme changes of temperature - the tube either needs to be vented or filled solid, and filled solid will probably become vented over time due to differences in CLTE.

[FLBentRider]

I also think the woven nature of the wire makes it hard to seal and also wicks moisture.

[KevinG]

I'm not sure about this, but I thought I remember someone having some luck with epoxy on the ends. I think it might have been Arnie.

[BuyLowSellHigh]

I also think the woven nature of the wire makes it hard to seal and also wicks moisture.

That woven metal covering is there for mechanical durability - if you open it up inside is the normal insulated wire.  If you have an Auber unscrew the connector end and you'll see the wires inside the sheath.  I could get past the metal sheath, but I can't get past the pressure changes that will occur with heating, which will lead to a vacuum when it cools and then suck up water.

Something like epoxy will probably work for a while, maybe a good while, but the difference in expansion will probably lead to microcracking over a longer period.  If you wanted to go that route the best would be to fill the tube when the probe is built.

edit - even though I can get past the woven metal sheath I can't get past two wires in one seal,  That creates a leak between the wires that can't be sealed with shrink tubing.

[HawkeyeSmokes]

I have heard of people having good luck using Hi-Temp RTV silicone to seal the wire/probe.

Been meaning to try it out.

[BuyLowSellHigh]

I'm having one of those Doh ! moments.

A couple of weeks ago the original meat probe that came with my Auber Dual Probe PID croaked (fortunately I had a spare set in hand).  A couple of days later I called Auber to get a replacement for the dead one and talked with Suyi about the probes.  He told me that the problems were with the meat probes and they are still trying to get the design and supplier right (there are two versions - one crimped, one sealed - both have their problems).  He also told me that they have no problems with the tower temp probes but their suppler for those refuses to make a bent probe.  He said folks like the bent version for meats because it gives them something to hold on to when removing it from a hot piece of meat.  I suggested to him that straight would be okay with me if it would be reliable (I can use a towel or mit).

Here's the Doh! part.  In the thread on using a crockpot for sous vide Sorce mentioned he bout a sous vide probe from Auber and is using it on his dual robe controller.  A quick look this morning on the Auber site and here is the type of probe used for bath temp control.  Note in the description is states "It is designed for continuously immersion application such as cooking sous-vide."  It looks much like the sensor used for tower temp control but with a different insulated lead.  So it seems I am back to the discussion I had with Suyi - can it be done for a meat probe that will take oven temps?

Anyone else think this is worth pursuing?