low temperature thermal grease?

[coppercone2]

I noticed I am using Arctic MX-6 grease to couple a cold fluid flow to something (ice cream machine) and that stuff basically turns into plastic at that temperature. Very solid

If its motionless and properly fixed at room temperature, does it matter that it turns into basically hard plastic when cold? Its like less then -35C

Am I losing thermal performance because of this ?

[thm_w]

https://www.arctic.de/media/77/c5/74/1666609891/Spec_Sheet_MX-6_EN.pdf
https://www.arctic.de/en/MX-6/ACTCP00080A

Spec is -50 so I'm not sure why you'd think there is a reason for concern just from temperature alone, assuming it doesn't go below that.
The bigger concern might be thermal cycling. But that should be more of an issue with thin pastes not thick ones.

https://www.lesker.com/newweb/fluids/greases-cryogenic-apiezon/apiezonn/

[wraper]

Being in solid state actually prevents pump out effect. Actually there are thermal interfaces that are solid at room temperature https://www.laird.com/products/thermal-interface-materials/phase-change

[coppercone2]

Ok yeah I read you can use indium foil for a thermal material too and that is basically solid. I was just thinking maybe it might behave differently when its frozen solid. It melts instantly if you pick it up.


Don't care too much about life span, I just was making sure its not a bottle neck

why? because its weird as hell to see it turn solid. It comes off really easily too (0 sticking power). But I made clamps with threaded rod to hold these things together

all this stuff is hard to probe BTW. Flow, temperature, pressure all require a shit load of accomodations for low temperature use when you are just screwing around.

[David Hess]

As long as the mounting pressure is maintained it should not matter.

[coppercone2]

it would be cool if there was super heated materials that are molten  that can be brought to a really low temperature and turn solid until molten again at a high temperature so you can do cryo molding

I wonder what year we get that technology

[coppercone2]

if you are curious I made a experiment where I put the thermal paste on two surfaces without tension. Its very fragile and does not stick to all surfaces. If you disturb it, it breaks the bond, typically sticking only to one surface and there is a drastic loss in heat flow.

so you can say that it gets rather fragile when its frozen solid. I suspect it might form a formidable glue between two microscope slides (smooth glass). It seems to stick poorly to textured surfaces

[Chalcogenide]

If you are concerned, you could use a low temperature thermal interface, like the Thermal Grizzly Kryonaut (specified down to -250 °C, but VERY expensive).

[coppercone2]

I got some GK. yeah it expensive