Silicone oil in thermowell

[BenniferBropez]

Hello all, I have a long thermowell I will use with an Ink bird ITC-308 probe. There is some play between the probe and the thermowell wall and I was looking at thermal paste to help the probe better read the temperature. Because the thermowell is long I am not able to use the applicator that comes with typical thick thermal paste I have seen sold online. It just won't reach that far.

I have read about silicone oil which is good at transferring heat and shouldn't corrode the probe and should not short out the probe as it seems to be a good electrical insulator. I am thinking of using a tiny bit of this in the thermowell since it will flow really well right down to the bottom without the need of an applicator. My probe is mounted vertically so it won't run out as it would if mounted horizontally.

I am thinking of using just enough so the tip of the probe is about halfway submerged. From what I have read it is nontoxic and isn't going to come in contact with the beer anyway.

Has anyone used silicone oil for this purpose?
Are there any problems that I might want to consider?

Thank you,
Ben

 

[doug293cz]

Haven't done it, but it should work, and I can't think of any possible issues (as long as you keep the tip below the entrance, which you already understand.)

Brew on

 

[homebrewdude76]

I bought some large tubes of thermo paste and packed my thermowells. So I got it in there..
But the response time seems slow to me, just wondering if something else would be "quicker"

 

[doug293cz]

I bought some large tubes of thermo paste and packed my thermowells. So I got it in there..
But the response time seems slow to me, just wondering if something else would be "quicker"

Thermal paste isn't a great conductor of heat, it's just much better than air.

How did you determine that it's the temp probe that is slow to respond vs. the point where you measure actually changes temperature slowly?

Brew on

 

[homebrewdude76]

Thermal paste isn't a great conductor of heat, it's just much better than air.

How did you determine that it's the temp probe that is slow to respond vs. the point where you measure actually changes temperature slowly?

Brew on

You are correct, I don't know. But when I dump 172 water in the kettle the temp probe is slow to respond.... Not even sure if it can be fixed.

 

[doug293cz]

You are correct, I don't know. But when I dump 172 water in the kettle the temp probe is slow to respond.... Not even sure if it can be fixed.

That seems like a good test of the response time.

As long as the temp sensor can respond faster than your system can actually change temperature it shouldn't make much of a difference. But if the system can change temps faster than the temp sensor can respond, that can lead to control problems (mostly over and under shoot of setpoints.)

Brew on

 

[homebrewdude76]

I was over/under shooting this past weekend on my HLT.
I was blaming the need to recalibrate the PID controller. Been a few years.

 

[jerrylotto]

If you increased the mass of the thermowell by adding thermal paste, it will take longer to respond to temperature changes.

 

[homebrewdude76]

If you increased the mass of the thermowell by adding thermal paste, it will take longer to respond to temperature changes.

Ok, understood.

But doesn't there have to be something aside from air in the well?

 

[jerrylotto]

Ok, understood.

But doesn't there have to be something aside from air in the well?

Depends on the probe's contact with the thermowell body. If it it a reasonably snug fit, then that works fine. If not, you only need to snug it up with something like a plastic straw along side the probe.

 

[homebrewdude76]

Mine is no where near snug. Hot dog in a hallway.... So I squeezed it 100% full of the paste.
I am sure there is a better way.