5 ms·

Is gallium foil sufficient?

bayindirh 5y ago
Using gallium as a heat transfer agent is very a very poor choice, considering it has a melting point of ~30 degrees Celsius, and a bog standard Raspberry Pi runs around 40-60 degrees Celsius range, depending on the load. I'm using Arctic Cooling's MX series thermal pastes for over a decade, and my eight year old MX-2 installation works as good as day one. It's taking heat away from an Intel i7 3770K, which is not a cool chip, esp. under load, and mine has seen some hotter days under constant load (with a scientific code which is designed to get as much performance possible from a processor, no less). I have a couple of these Cooler Master cases too, and their out of the box pastes are doing a good job for now. So, I'd rather not fix something if it's not broken. If the temps start to climb, I already have more than enough spare of the paste I use in my systems.
- enchiridion 5y ago
  Definitely, thermal paste is the answer for any practical application. Ah you’re right. I was thinking of experiments with indium foil I had seen[1]. Plus gallium is used in the pastes apparently. So if the goal is a very long term thermal interface material, I don’t think pastes are the best. A homogenous solid is likely to last longer. Indium foil fits the bill nicely. Also thermal pads or graphite pads, but I’m not sure how long they last. [1] https://www.reddit.com/r/buildapc/comments/99fq4y/experiments_with_indium_instead_of_thermal_paste/ https://www.reddit.com/r/buildapc/comments/99fq4y/experiment...
  - bayindirh 5y ago
    > So if the goal is a very long term thermal interface material, I don’t think pastes are the best. A homogenous solid is likely to last longer. Arctic Cooling states that MX-5 is guaranteed to keep its performance its for 8 years [0]. Considering this stuff is made to interface with 200W+ CPUs, cooking it dry with a Raspberry Pi is very unlikely. As I said before, I'm cooking MX-2 in two different systems (Q6600 & i7 3770K) for 8 years, and they didn't lose their transfer performance a bit. From my experience, thermal pads and solid interfaces do not transfer with the same efficiency and cannot absorb heat spikes as well as a good thermal paste. I run my OrangePi Zero with a thermal pad interface to a small heat-sink and that thing runs uncomfortably hot. I can't transfer data faster than 40mbps for a long time or run CPU intensive stuff, because it gets hot, fast. Its form factor and case doesn't allow for a more robust solution either. Of course the choice is yours, but in my experience, when compared to older paste, or to ordinary white stuff, current generation stuff is leaps and bounds ahead. Especially, Arctic Cooling. [0]: https://www.arctic.de/en/MX-5/ACTCP00047A https://www.arctic.de/en/MX-5/ACTCP00047A
    - labawi 5y ago
      Thermal pads are way thicker and typically higher resistance - even good and thin ones are worse than standard paste and basically useless over a dozen watts (depending on surface area * temperature difference). OTOH, used properly, liquid (liquefying) metal should have a better transfer efficiency than paste. If you have issues, you can also try lapping the surfaces.
      - bayindirh 5y ago
        The sinks I use have 3M integrated pads. They might not be the highest performing ones, but they're pretty decent for their size. As I've said, it's attached to a OrangePi Zero which has a very small, epoxy packaged CPU. So tension-mounting, lapping, or using higher end compounds are out of question. The whole point of OrangePi Zero is being small all over, so it's happy temp-wise with its normal load, I'm not planning to work on it further for now. Raspberry Pi 4 is different and has a whole-body heatsink, and its paste is good for now. If it starts to lose cooling capacity, that'll be a different matter all-over.

Using gallium as a heat transfer agent is very a very poor choice, considering it has a melting point of ~30 degrees Celsius, and a bog standard Raspberry Pi runs around 40-60 degrees Celsius range, depending on the load. I'm using Arctic Cooling's MX series thermal pastes for over a decade, and my eight year old MX-2 installation works as good as day one. It's taking heat away from an Intel i7 3770K, which is not a cool chip, esp. under load, and mine has seen some hotter days under constant load (with a scientific code which is designed to get as much performance possible from a processor, no less). I have a couple of these Cooler Master cases too, and their out of the box pastes are doing a good job for now. So, I'd rather not fix something if it's not broken. If the temps start to climb, I already have more than enough spare of the paste I use in my systems.

enchiridion 5y ago
Definitely, thermal paste is the answer for any practical application. Ah you’re right. I was thinking of experiments with indium foil I had seen[1]. Plus gallium is used in the pastes apparently. So if the goal is a very long term thermal interface material, I don’t think pastes are the best. A homogenous solid is likely to last longer. Indium foil fits the bill nicely. Also thermal pads or graphite pads, but I’m not sure how long they last. [1] https://www.reddit.com/r/buildapc/comments/99fq4y/experiments_with_indium_instead_of_thermal_paste/ https://www.reddit.com/r/buildapc/comments/99fq4y/experiment...
- bayindirh 5y ago
  > So if the goal is a very long term thermal interface material, I don’t think pastes are the best. A homogenous solid is likely to last longer. Arctic Cooling states that MX-5 is guaranteed to keep its performance its for 8 years [0]. Considering this stuff is made to interface with 200W+ CPUs, cooking it dry with a Raspberry Pi is very unlikely. As I said before, I'm cooking MX-2 in two different systems (Q6600 & i7 3770K) for 8 years, and they didn't lose their transfer performance a bit. From my experience, thermal pads and solid interfaces do not transfer with the same efficiency and cannot absorb heat spikes as well as a good thermal paste. I run my OrangePi Zero with a thermal pad interface to a small heat-sink and that thing runs uncomfortably hot. I can't transfer data faster than 40mbps for a long time or run CPU intensive stuff, because it gets hot, fast. Its form factor and case doesn't allow for a more robust solution either. Of course the choice is yours, but in my experience, when compared to older paste, or to ordinary white stuff, current generation stuff is leaps and bounds ahead. Especially, Arctic Cooling. [0]: https://www.arctic.de/en/MX-5/ACTCP00047A https://www.arctic.de/en/MX-5/ACTCP00047A
  - labawi 5y ago
    Thermal pads are way thicker and typically higher resistance - even good and thin ones are worse than standard paste and basically useless over a dozen watts (depending on surface area * temperature difference). OTOH, used properly, liquid (liquefying) metal should have a better transfer efficiency than paste. If you have issues, you can also try lapping the surfaces.
    - bayindirh 5y ago
      The sinks I use have 3M integrated pads. They might not be the highest performing ones, but they're pretty decent for their size. As I've said, it's attached to a OrangePi Zero which has a very small, epoxy packaged CPU. So tension-mounting, lapping, or using higher end compounds are out of question. The whole point of OrangePi Zero is being small all over, so it's happy temp-wise with its normal load, I'm not planning to work on it further for now. Raspberry Pi 4 is different and has a whole-body heatsink, and its paste is good for now. If it starts to lose cooling capacity, that'll be a different matter all-over.