Liquid Metal Explained: How it works, why it fails (and how to use it)

Discussion in 'Hardware Components and Aftermarket Upgrades' started by margroloc, Sep 27, 2017.

Thread Status:
Not open for further replies.
  1. Papusan

    Papusan JOKEBOOK's Sucks! Dont waste your $$$ on FILTHY

    Reputations:
    22,603
    Messages:
    23,571
    Likes Received:
    40,875
    Trophy Points:
    931
    Don't compare RTV Silicone Gasket Maker with Super Glue.
     
    Ashtrix and Falkentyne like this.
  2. yrekabakery

    yrekabakery Notebook Virtuoso

    Reputations:
    754
    Messages:
    2,358
    Likes Received:
    2,271
    Trophy Points:
    181
    Exactly. I could easily see this damaging the PCB if the user isn't careful. Idk what kind of super glue they used, but the Loctite gel stuff I've used is nowhere near as difficult to remove.

    RTV silicone is much easier to remove than super glue, you can scratch all of it off with just your fingernail.
     
  3. dellienware owner

    dellienware owner Notebook Evangelist

    Reputations:
    26
    Messages:
    325
    Likes Received:
    8
    Trophy Points:
    31
    my liquid metal applications have evaporated, what did id do wrong?
     
  4. Falkentyne

    Falkentyne Notebook Prophet

    Reputations:
    7,209
    Messages:
    5,456
    Likes Received:
    7,548
    Trophy Points:
    681
    Did the temps "rise" at all before you checked this?
    LM gets "partially" absorbed by copper due to a battery effect, leaving a hardened material outside. It does NOT degrade the copper or destroy its structure like it does aluminum.
    This effect can be circumvented by applying *more* LM than you are supposed to. This will allow the LM to do its thing and have it partially absorbed by the copper, and the remaining LM will remain outside when the battery effect is stabilized. You need to apply a bit of "extra" LM for this to allow for this. LM is VERY VERY thin, like water, so if even a micronnanometer layer of it gets absorbed, if you tried to apply the bare minimum to get by, it could leave none left on the CPU :)

    Another secret is to 'force' LM absorption into copper at the very beginning by 'tinning' the heatsink with LM. Take your applicator and rub LM *vigorously* into the copper right above where the CPU or GPU will sit and do a lot of strokes and rubs. This will 'begin' the battery effect early by causing part of the LM to begin working its way into the outer layer of the copper. Then attach the heatsink.

    This method also works very well with IHS delids. People have tested and confirmed that "tinning" the inner side of the IHS when doing cpu delids, with liquid metal, lowers temps than just only applying LM on the core by itself. Because a tiny bit of LM also works its way into imperfections in the nickel layer as well (just not as much as into copper).

    BTW, copper doesn't completely absorb all LM deeply. it only gets absorbed into the very outer layer. You can actually clean this layer with 3000 grit sandpaper and Isopropyl alcohol and have the copper look like new again.

    Also make sure the CPU/GPU surface and heatsink is fully flat. A fully flat surface keeps good contact with any LM that may have gotten absorbed, and if you used enough to make up for this absorption and tinned the heatsink, you will be good to go after even 1 year.

    Like seen here:

    http://forum.notebookreview.com/threads/after-1-year-of-thermal-grizzly-conductonaut.799343/

    Convex/concave heatsinks will fare far worse.
     
    pressing likes this.
  5. senso

    senso Notebook Deity

    Reputations:
    244
    Messages:
    730
    Likes Received:
    174
    Trophy Points:
    76
    After one year and maybe a couple months, here is the heatsink of a Toshiba L50-A, BIOS "modded" to allow for more than 30Amps into the CPU, before it was neutered to 30Watts TDP max, CPU side was lapped, GPU left as-is, because on this laptop I never use the GPU, its for work, running CAD software and a couple VM's.

    It was getting very loud under light loads, and today I verified that it was hitting almost 70ºC with 8Watts of package TDP..
    IMG_20180514_214219.jpg IMG_20180514_214242.jpg IMG_20180514_214300.jpg IMG_20180514_214251.jpg
     
  6. dellienware owner

    dellienware owner Notebook Evangelist

    Reputations:
    26
    Messages:
    325
    Likes Received:
    8
    Trophy Points:
    31
    Call me crazy, but after having so much evaporate it became hard to spread the LM around. So this time i'm going to mix it with regular paste to see if i can get it to spread and make better contact. Also may need to order a shim, but what size for my p377 sm-a?
     
  7. Falkentyne

    Falkentyne Notebook Prophet

    Reputations:
    7,209
    Messages:
    5,456
    Likes Received:
    7,548
    Trophy Points:
    681
    Why would it be harder to spread? You're supposed to use polishing sandpaper (2000+ grit, 3000 is best to avoid any sanding of the copper) to remove the hardened LM and any tiny artifacts from the stain remaining (the stain itself is fine as long as its perfectly 100% flat). If you are putting new LM on top of hardened oxidized LM, that's very bad because you will instantly have bad contact.
     
  8. dellienware owner

    dellienware owner Notebook Evangelist

    Reputations:
    26
    Messages:
    325
    Likes Received:
    8
    Trophy Points:
    31
    there wasn't any hardened LM that I saw except along the edge, the rest created a light film that was microscopic. NO REASON,that the LM should've stayed in a ball form. Plus my idle temps differ by 2c between the TG-7/TGC and just TGC
     
    Last edited: May 14, 2018
  9. jaug1337

    jaug1337 de_dust2

    Reputations:
    2,134
    Messages:
    4,871
    Likes Received:
    1,030
    Trophy Points:
    231
    Beautiful guide! Well done
     
  10. Falkentyne

    Falkentyne Notebook Prophet

    Reputations:
    7,209
    Messages:
    5,456
    Likes Received:
    7,548
    Trophy Points:
    681
    N
    #1:
    LM will remain in a ball form if there is any residue of isopropyl alcohol or any other foreign liquid on the CPU or heatsink surface. Isopropyl alcohol causes the LM to fail to be attracted to the surface and the attraction to itself remains stronger, so there must be no wet residue on the surface or applicator. Make sure your applicator is 100% clean! Do not reuse any dirty applicators!!

    2) This is the absolute best applicator of LM I have ever used:
    https://www.amazon.com/gp/product/B00Q3BG6Y4/ref=oh_aui_detailpage_o03_s00?ie=UTF8&th=1

    3) The MAIN LM application should be applied to the CPU or GPU surface directly and spread there, NOT to the heatsink (EDIT** I did not say do NOT apply LM to the heatsink. I said do not make this the MAIN application! You "Tin" the heatsink (apply a thin layer and rub it in extremely well and hard to make it begin to react with the copper. That's what I mean, sorry for any confusion). You spread it until it is fully spread around the CPU or GPU. Make 100% sure that the spread leaves an equal amount of LM around the entire silicon without any "barely any there" parts! That is because LM will attract and try to adhere to itself, so its possible any "barely any there" parts can be 'sucked' into the "more here" parts when applying the heatsink, causing hot spots, premature oxidation (absorption of part of the LM into the copper, leaving a hardened residue behind), and core temp differentials. I have found it is better to use a little too much LM than too little!!! But you must exercise care! To use a little too much, use nail polish coats around all SMD resistors around CPU or GPU, then for more OCD protection, you can cover even that with Super 33+ tape (note: you only need to do either the super 33+ method or the nail polish coat method, not both) and finally, since you went with the "little too much" method, finally, you use a very very highly compressible, cutout, and THIN (even if you have to trim the foam thickness) foam dam barrier, to trap any excess LM from ever escaping the area, in case of a bump or shock. The tape or nail polish doesn't prevent this at all--that only stops shorts or dead hardware from LM touching the SMD's right next to the chip. The foam dam protection stops LM from getting on the main PCB, permanently.

    That foam dam must be compressible with NO EFFORT, using your fingers, to the width of a human hair.

    Once you are done spreading the paste on your CPU or GPU fully, then you take the remnants remaining on your applicator and you "Paint" that on the heatsink, in the shape and size of your CPU and GPU area :) Rub it in well; this accelerates and begins the LM "absorption" from that coat right away, rather than having it begin from the layer on the CPU or GPU.

    This is my method. And I enjoy it.

    My method makes the LM look more like spreading honey on something, rather than a super ultra thin later like some repasters here tell you to do. This gives a bit extra room for any absorption and helps longevity.

    LM is best done with a perfectly fully flat heatsink! If you have >4C core temp differentials with REGULAR PASTE using a fully 100% all thread balanced load like prime95 (AVX disabled), you are going to have problems with LM--it means you hae either a convex or concave or imbalanced heatsink, and may need to take sandpaper to it with a sanding block or kit (which requires removing the springs and screws; some may be impossible to take a sanding kit to).

    Avoid any items with COTTON. Avoid Q-tips for that reason. Even $1 'white foam' type swabs (for eyebrow/eyelash care) from the 99 cent store will work, but it will be hard to control proper LM spread with precision because they will be a bit too "thick" and round. The applicators (also for eye care) I linked are much thinner and allow far more precise spreading and are even reusable as long as you store them in a dust proof ziploc type pouch (the old LM should not harden on them).
     
    Last edited: May 27, 2018
  11. rancid

    rancid Notebook Evangelist

    Reputations:
    562
    Messages:
    647
    Likes Received:
    245
    Trophy Points:
    56
    @Falkentyne If I read this correctly, you are saying not to apply any LM to the heatsink at all before applying it? I've been doing LM on the CPU die and a thin layer on the heatsink but am questioning how well I am lining up the heatsink to where the actual die is when I "paint" on the LM.
     
Loading...
Thread Status:
Not open for further replies.

Share This Page