Why you shouldn't use Liquid Metal...(MSI GL62M)

Discussion in 'MSI Reviews & Owners' Lounges' started by hmscott, Feb 24, 2020.

  1. hmscott

    hmscott Notebook Nobel Laureate

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    Timmy Joe discovers the laptop he re-pasted with Liquid Metal is now overheating, and after opening it up finds the Thermal Grizzly he used has "dried up" - interacted with and was absorbed into the copper - so he is having uneven coverage between the heatplate and CPU showing 2 hot cores.

    He has some other content first, but starting @ 04:25 he works on the laptop, you can see the effects of time on the Liquid Metal starting @ 08:50 when he tries to pry the heatsink array off the board.

    He does a pretty good job of cleaning it, but perhaps it needed a bit more work before he made the video...

    Why you shouldn't use Liquid Metal...
    Feb 18, 2020
    Timmy Joe PC Tech
    I used liquid metal on my laptop about a year ago and lately it has been loud, overheating and blue screening. Turns out it's not a good idea to use Liquid Metal directly on copper...
     
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  2. TheReciever

    TheReciever D! For Dragon!

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  3. hmscott

    hmscott Notebook Nobel Laureate

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    It chemically interacts with the Copper over time with the heat and pressure assisting. That's why he can't wipe it off or brush it off, it's into the metal. Sanding it down is the only way to scrap it off.

    This is how all liquid metal applications end over years of interaction. He could have re-pasted every 6 months or a year to keep it "fresh".

    Because he gave it to his wife who wasn't watching the rising temps it was able to continue unabated until it finally ended up wailing it's fans even at idle.

    This is what a number of us have been pointing out for many years. Don't screw with Liquid Metal, just get a nice non-conducting paste and be happy with a few degrees less cooling.

    In the long term you'll still need to re-paste that too. Which is why if you can, simply undervolt and limit FPS to reduce your thermals so the stock paste can suffice. The manufacturer paste is less impressive in cooling temps but it's designed to last for years, so the laptop maker doesn't get them back as RMA to re-paste.

    When I went looking for a place to post this I found the threads that have lots of posts about this have been closed - timed out. I'll update later with links to those threads.
     
  4. TheReciever

    TheReciever D! For Dragon!

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    Im aware of that, which is why people like to do pre-application to let it soak. Simply drying out though is usually due to insufficient pressure
     
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  5. Khenglish

    Khenglish Notebook Deity

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    I have not found more pressure to make liquid metal last longer. If anything a slightly thinner material from more pressure needs to be redone sooner. I have always found copper heatsinks need to be sanded and redone about twice per year. I'm fine with this though as I mess with my computers a lot, but OEMs definitely should not be shipping out systems with liquid metal on copper.

    Nickel plated heatsinks do not have this issue and seem to last indefinitely.
     
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  6. hmscott

    hmscott Notebook Nobel Laureate

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    There is always an air leak around the edges of the imperfect fit between the IHS / Die / heat plate.

    The worse it is the quicker the drying out, but even a good fit will eventually pump out given enough time.

    His application sounds like it was about 3 years ago, plenty of time to overheat and cook it to the point it looked when he pulled it apart.

    Typically laptops are worse than desktops for a few reasons. Fitment is the top reason, movement flexing joins is the next, and low mounting pressure due to the lack of leverage with those light components is the other. The heatpipes stretched out and pushing against the pressure - to the point of "popping" if over torqued. I've heard them pop after assembly... very depressing.

    It's just not a good material to use for a paste in the format we use normal non-conductive pastes. If there was a captive closure that assured no leaking and no air exchange it would be far better, but that kind of engineering investment hasn't been done yet.

    Heck we don't even have active cooling for NVME controllers for Gen3 or Gen4 Storage. There's a lot of engineering needed to clean up laptop thermals.
     
  7. hmscott

    hmscott Notebook Nobel Laureate

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    You've got all that right. As long as you enjoy it why not do it. :)

    For most people that just want to enjoy their laptops for their gaming or other uses that get sucked in to getting LM for the cooling they don't know about the need to reapply the LM on a regular basis and it's a surprise for most.

    It's the sales guys that want to make money that conveniently forget to mention these details, or explain it away as a unusual event that rarely happens.

    It you don't want to redo the paste on a regular basis don't re-paste or change the stock paste in the first place. It's designed to last for years out of the factory. It's not the best at lower temps but it's designed to not require repasting during the life of the laptop.

    If you can undervolt, limit FPS, or otherwise cool the CPU / GPU under thermal throttling for your use you don't *need* to repaste.

    Repasting is a hobby unto itself. With all of the enthusiastic recruiting to get everyone to experience it it's hard to resist. :)
     
  8. Mr. Fox

    Mr. Fox BGA Filth-Hating Elitist

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    Yes, that is generally the case. Some of the laptop heatsinks I have seen over the years are kind of sketchy and the copper sometimes seems abnormally porous (absorbent) and it may not stop soaking up the liquid metal until the second or third application. I've actually seen that happen with other thermal pastes as well. Liquid Metal will get a little crunchy around the edges where it is exposed to air, but the part that is sealed will never dry out. The older Alienware systems back when QC was something they paid attention to (M18xR1/R2, Alienware 18 and Alienware 17) had heat sinks that fit fantastic. I've taken them off a year later and just spread around the liquid metal that was already there and put it back together again. @Papusan got something like 3 or 4 years (don't remember exactly how long) out of one application of liquid metal on his Alienware 17 (Ranger).

    Nothing works better than liquid metal when the fit is excellent. It's the perfect TIM in that scenario. Extremely effective and nothing is more durable. When the fit is not excellent, it's crap. It's ineffective and not durable when the fit is crappy. I typically see (and expect) anywhere from 10° to 20°C reduction in load temps on my overclocked systems. The only times I have not seen remarkable thermal improvements is with poorly fitting heat sinks or improper application. Even when running bare die with the 7960X and 7980XE I see about a 20°C improvement in load temps compared to the best enthusiast TIMs (Kryonaut, Gelid, Phobya Nanogrease, etc.). The ordinary TIMs tend to act as an insulator and tend to trap heat on the chip instead of moving it to the heat plate. The higher and more aggressive the overclock, the more effective liquid metal is. Running stock, the temperature improvements are still there, but much smaller (like around 5° to 10°C improvement).

    Unless I have a system with sloppy fitting parts that do not allow me to use it, I won't use anything except liquid metal any more. It's vastly superior when parts fit properly.

    Edit: people that have major issues with liquid metal drying out due to sloppy fitting parts are going to have problem with other TIMs as well. The underlying problem is magnified with liquid metal. The only thing that works well are super thick TIMs, like IC Diamond or the thick waxy thermal pads. The thermal conductivity of the TIM is less important in that scenario, as the most important thing is plugging the gap so there is something to carry the heat from the chip to the heat plate. Air doesn't work well, LOL. If it is not something thick, the paste will either pump out or dry out within a matter of days, or in just a couple of weeks. Chassis flex can also be a problem. If the chassis twists and flexes every time you pick it up, keeping the TIM where you placed it in the beginning is going to be problematic. Greater rigidity in the laptop chassis generally contributes to the longevity of thermal compound effectivness.
     
    Last edited: Feb 24, 2020
  9. Friedhelm Schröter

    Friedhelm Schröter Newbie

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    I am trying to understand how useful liquid metal is, this means what happens when liquid metal is applied in different scenarios. I find a lot of conflicting/contradicting statements, also in this thread of 8 comments and would like to explain my current model of understanding by highlighting where I agree, but also to explain where my view is completely different together with the reason or reasons I see it completely different.
    Ideal would be to get some feedback from people with a lot of knowledge and practical experience or advice to another thread where liquid metal is or was discussed quite deeply to improve my model of understanding.

    I fully agree to the first quote. Due to its quite high thermal conductivity of 40 to 80 [W/m-K] in combination with possibly very thin layers (when both surface forms fit well and there are no mechanical limitations like the U-form of a IHS/lid) only solid metals as silver/copper/aluminum/… can transfer/conduct heat better than liquid metal (but solid is not really usable for gaps that might change their form with temperature or are showing different thermal expansion), while materials like graphite or micro-diamonds with even higher thermal conductivity than solid metals each have their specific problem (graphite is not yet {or ever?} possible to realize in the thinness of thermal grease/liquid metal and micro-diamonds cannot realize a large contact area and their hardness causes surface damage when pressed onto/into solid surfaces).
    Concerning the second quote I agree to its first part, due to immediate, but only thin oxidation the surface exposed to air gets crunchy. But I think think this oxidation of gallium on air has no real effect on the thermal resistance {it would only be harmful if oxidization would continue}, but surface oxidization influences strongly how well a surface can be wetted (how low the contact resistance of 2 different materials is) as it results/support to form the ball forming of liquid metal.
    But in my try to understand what is happening around liquid metal I do not agree to the second part of the first quote. In case of non-conductive thermal grease I understand the dry out has something to do with the de-composition of the mixed materials and evaporation of the material into air that keeps the grease flexible (this means in case of thermal grease sealing to reduce the evaporation into air would have an effect on longevity).
    In case of liquid metal however evaporation into air would start only at temperatures above 1.000°C, but "dry out" hardening is rather the result of migration/diffusion of gallium into copper to form the alloy CuGa2, which you find on copper after a longer exposition to liquid metal as a mechanically stable thin silver colored surface. This thin CuGa2 layer results in negligible worse thermal temperatures, because even though the thermal conductivity is reduced to 95 [W/m-K] for the alloy CuGa2 compared to about 400 [W/m-K] for pure copper, the thickness of the CuGa2 layer is extremely thin. The "dry out" hardening of liquid metal is in my understanding caused by the fact, that reduction of the gallium percentage in the liquid metal (because the gallium disappears/migrates/diffuses into copper and at much slower speed also into nickel) will increase the melting temperature, so that first a little of the liquid metal sets down as solid metal on the surfaces and with steadily migrating/diffusing away gallium eventually all remains of the liquid metal will become hard at room temperature causing large temperature up on the silicon chip either by the creation of a large void in the gap (steadily less contact area) as the liquid metal volume becomes less and less or at gaps having excess liquid metal it gets first completely hard and then cracks under the mechanical stress of repeated thermal changes. Sealing cannot have any effect on the "dry out" hardening process because it happens based on migration/diffusion of a liquid metal/gallium into a solid metal it cannot be sealed off. The main factors for the speed with which liquid metal "dries out"/becomes hard should be: 1) the material the liquid metal/gallium is in contact with (migration/diffusion into copper is fast, into nickel is slow and into silicon is barely noticeable if happening at all) 2) the thickness of the liquid metal gap (the thicker the longer it takes to dry out), 3) the size of the contact area (porosity or fine scratches result in larger effective contact area, faster dry out) 4) the temperature (the higher the temperature, the faster happens the diffusion).

    When my basic understanding on the completely different dry out processes on liquid metal compared to thermal grease is correct, this should also mean that a high pressure heat sink (resulting in lowest thickness liquid metal) should dry out faster, simply because the speed of gallium to leave/form CuGa2 will be the same, but the amount of gallium is much less.
    When you put on the other side some storage in form of a foam ring around the liquid metal the time to dry out should take longer, because the gallium migrated into the copper will partly be replaced from gallium/liquid metal stored in the foam, as long as both stay in contact.

    Out of above model of understanding my personal conclusions on liquid metal are:
    1) Liquid metal is well usable on nickel (Ni) plated copper (require no or rare reapplication/renewal of the liquid metal due to "dry-out" hardening, because gallium's speed to migrate/diffuse into nickel is low).
    2) Liquid metal is usable/effective on copper, but because the speed of "dry out" is much faster than on nickel, you have to accept to replace the liquid metal each half a year (or whichever time your specific application process/surrounding allows the liquid metal to stay liquid/be removed effortless).
    In addition:
    3) Liquid metal has the general problem of leakage (this means danger of catastrophic PC/graphic card failure by causing either electrical short or in longer term destroying solder joints), because it is of low viscosity and nobody can control the amount applied, the contact pressure applied and the changes of forms by temperature in such a way that no spillage will occur. This means precautions to prevent short/contact are absolutely mandatory and good security is given by following 2 step precaution:
    a) Coating of close by capacitors/resistors by either nail polish or any other coating (should be long term stable against liquid metal) or a tape suitable for at least 100°C (Kapton, …).
    b) Setting a barrier around the liquid metal so that spilled small balls cannot roll to/reach any dangerous point (for example a compressible foam ring {on a CPU the lid acts as such barrier}).
    4) Liquid metal shows great reduction of temperatures (-10/-20°C) at high load (this means chip temperatures close 90°C) only when it is applied as first TIM directly onto the small surface silicon chip, while when applied as second TIM on top of an IHS/lid to an air or water based cooler its effect is much smaller (-1/-3°C). Seeing the need for permanent renewal of the liquid metal and its required precautions only extreme enthusiasts looking for highest overclocking may apply liquid metal on top of an IHS/lid while most people will use for the second TIM the much more easy and simple to use thermal grease accepting the 1 or 3°C higher temperatures to get much longer longevity {not required to reapply each 6 months and no trouble with leakage causing a short or destroyed solder joint}).

    The oxidation of liquid metal on air is in my understanding the reason why it is absolutely necessary to wet both opposite surfaces. When both surfaces are wetted the oxide cannot harm, while when only one side is wetted, the thin oxide layer on the liquid metal may hinder most area on the opposite side to get wetted which results in strongly higher thermal resistance.

    Some comments on detailed wordings in the first 8 comments in this thread, which I think are misleading for people with few knowledge or even show completely wrong understanding:
    Instead of "He could have re-pasted every 6 months or a year to keep it "fresh"" more correct wording should be "Liquid metal on copper MUST be replaced every 6 months or whichever time a specific attachment process keeps the metal liquid/easily removable".
    Instead of "Don't screw with Liquid Metal, just get a nice non-conducting paste and be happy with a few degrees less cooling" the sentence "If you do not want to replace liquid metal on top of an IHS/lid each 6 months to get just 1 or 3°C down, accept the slightly higher temperature and go with thermal grease offering much longer longevity than liquid metal and no danger of catastrophic short damage" would be much clearer.
    The sentence "Simply drying out though is usually due to insufficient pressure" is in my understanding nonsense, as higher pressure has basically no effect or rather the contrary effect (as it reduces the available gallium amount to the minimum, a shorter time to dry out is the consequence).
    When someone is determined to use liquid metal as "I have always found copper heatsinks need to be sanded and redone about twice per year" I personally would question the process to sand the copper heatsink. Clearly the remains of the liquid metal must be removed, but this should be done without sanding (rather heat up to liquify the hard remains or use a soft acid/stop) to leave the silver color CuGa2 layer on the copper as this means this thin CuGa2 layer may reduce the speed gallium can migrate from newly applied liquid metal more deep into the copper (behind the CuGa2 layer).
    On the out of theme sentence "Heck we don't even have active cooling for NVME controllers for Gen3 or Gen4 Storage. There's a lot of engineering needed to clean up laptop thermals." I think current Gen 3 controllers are at the limit and PCIe Gen4 storage will only be widely applied once the efficiency of the controllers has increased to a level that allows usage without active cooling, clearly the preferred way for laptops.

    With my model I can explain most statements made above or elsewhere. But for a sentence like "Papusan got something like 3 or 4 years (don't remember exactly how long) out of one application of liquid metal on his Alienware 17 (Ranger)" my model does not provide an easy explanation. A longevity of 3 or 4 years on copper is a much longer time than I would expect seeing a general saying to replace liquid metal after 6 months (and some people say they even experiencing high temperatures in less than 6 months). But trying to explain this unusual long time by "better fit" is not really convincing me as my model says "better fit" means less gallium available, this means shorter longevity. Many people inform too few facts because they look for only one main cause of influence. In case of liquid metal however several causes can add up and result in a quite strong deviation from a general recommendation, like quite low average temperatures/few use, rather thick liquid metal when applied on a silicon die and a low reaction speed surface condition could result in such extreme deviations when all added up in an the same direction.
    My point is, most people see clearly liquid metal is not allowed on aluminum because the alloy gallium forms with aluminum is mechanically very brittle/has extremely low thermal conductivity and gets eaten away by air, but they do not see that gallium also migrates/diffuses into copper (and at less speed into nickel) which in turn reduces the gallium percentage in the gap resulting in "dry out" hardening as the melting temperature of the remaining liquid metal gets higher and higher with the ever lower percentage contents of gallium.
     
    Last edited: Mar 28, 2020
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  10. Mr. Fox

    Mr. Fox BGA Filth-Hating Elitist

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    Wow, that is quite the wall of text, bro. You burned a lot of calories on that. Your thoughts are clear and easy to understand, but it seems you are making something simple unnecessarily complicated.

    I use liquid metal because it is far and away better and produces amazing results compared to ordinary pastes, none of which compare. And, I have found it to be far more durable. Consequently, I cannot justify wasting my money or time using anything else. I have been using it for a very long time, and always do so where I can.

    The exceptions are use on aluminum and poor fit, but both of those exceptions are an unfavorable reflection on the product manufacturer, not liquid metal. In these scenarios the only option is to settle for something functionally inferior. I have had to use something inferior due to poor fit a few times and that always leaves me dissatisfied with the poorly engineered product rather than the liquid metal.

    Rather than trying to explain everything, the best approach is to just use it. If it works better, as it has proven to for many, keep using it. If it doesn't work better, which has been the case for some, then use something else.
     
    Last edited: Mar 28, 2020
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