Foam dam barriers for Liquid Metal safety insurance guide.

Discussion in 'Hardware Components and Aftermarket Upgrades' started by Falkentyne, May 21, 2018.

  1. jl1728

    jl1728 Notebook Enthusiast

    Reputations:
    15
    Messages:
    30
    Likes Received:
    16
    Trophy Points:
    16
    Sorry for replying to an old thread but i'm looking to do this and have some foam that will fit the bill. I can't see it surviving any sort of heat however. These things rest under the heatsink, aren't they going to melt?
     
  2. Mr. Fox

    Mr. Fox BGA Filth-Hating Elitist

    Reputations:
    31,618
    Messages:
    36,074
    Likes Received:
    58,769
    Trophy Points:
    931
    Not likely. They never melted on me. I did not use any kind of special heat-resistant foam.
     
    Last edited: Sep 17, 2018
    Papusan, jl1728 and Falkentyne like this.
  3. Falkentyne

    Falkentyne Notebook Prophet

    Reputations:
    7,760
    Messages:
    5,672
    Likes Received:
    7,983
    Trophy Points:
    681
    I have VERY VERY VERY thin extremely porous foam i trimmed down to 0.2mm andit lasted fine through 85C temps. You are fine. Foam will not combust. Even if slightly "melts" slightly (for lack of a better word) it still protects fine. I've tested several kinds of foam and the most thin most compressible "weak" foam works best especially when trimmed to 0.2mm. The foam that does NOT work is 'thick' non compressible foam or any foam that offers resistance to pressing. If you can take a square block of the foam at 3mm thickness and compress it to the width a human hair with your fingers without any resistance, that will work great. But on BGA weak heatsinks, I would trim the foam to 0.2mm.
     
    FrozenLord, Dr. AMK, Papusan and 2 others like this.
  4. jl1728

    jl1728 Notebook Enthusiast

    Reputations:
    15
    Messages:
    30
    Likes Received:
    16
    Trophy Points:
    16
    Not my image but this is the same exact model. Am I correct in assuming the foam barrier would go around the heat-resistant rubber pad that is already surrounding the GPU? The foam I have is extremely porous open-celled foam, i'm pretty sure I could shave it down to 0.3mm at least, if not thinner. Sorry for asking so many questions, but I think this is something I want to fully grasp before I even think of attempting it lest I goof everything up permanently.
     

    Attached Files:

  5. Falkentyne

    Falkentyne Notebook Prophet

    Reputations:
    7,760
    Messages:
    5,672
    Likes Received:
    7,983
    Trophy Points:
    681
    It goes right on top of the pad. What sort of pad is on that thing anyway? Never seen anything like that.

    The thinner the foam is, the better. The goal is to 'block' any tiny air spaces that exist between the area 'outside' of the GPU slug, between the GPU housing and the heatsink, where liquid metal can slide along either the black coating thing, or the outside of the heatsink. Even a barrier 0.2mm thick (as long as it offers NO resistance to being compressed to the width of a human hair) will block liquid metal nicely.
     
  6. jl1728

    jl1728 Notebook Enthusiast

    Reputations:
    15
    Messages:
    30
    Likes Received:
    16
    Trophy Points:
    16
    It feels like either very dense foam or even rubber. It's shorter than the die and I can only guess that it's some sort of thermal barrier for components around or under the die.
     
    Falkentyne likes this.
  7. yrekabakery

    yrekabakery Notebook Virtuoso

    Reputations:
    923
    Messages:
    2,729
    Likes Received:
    2,578
    Trophy Points:
    181
    I had that black plastic around my GPU as well. It doesn't protect the SMD components around the GPU die from LM, which can still flow under it, so just rip it off and apply nail polish or Kapton/Super 33+.
     
    Papusan, Mr. Fox and jl1728 like this.
  8. Falkentyne

    Falkentyne Notebook Prophet

    Reputations:
    7,760
    Messages:
    5,672
    Likes Received:
    7,983
    Trophy Points:
    681
    This.
    This.

    Here is what I found out btw from my own tests.
    Nail polish results in lower temps (and SHOULD absolutely *SHOULD 100% be applied on any delids to coat any resistors inside the CPU; I think this applies more to HEDT processors as I don't think the 7700K and 8700K have any exposed SMD's, although there are trace marks, and I have no idea if those NEED to be insulated or not), but when Liquid metal is applied on nickel plated copper, you are fine just using nail polish (IHS delids) or nail polish+foam dam on direct die BGA. But if you are using a copper heatsink, then it's best to use Super 33+ tape+foam dams. It's not because of nail polish not working, but rather because of the risk of increased oxidiation if the heatsink contact is not high pressure and has ANY flaws in it at all. A convex heatsink will cause air (even a TINY BIT) to get between the cpu slug and heatsink which will cause increased oxidation, which leads to accelerated absorption of the gallium into the copper. The layer of super 33+ tape actually decreases the amount of air space between the heatsink and the cpu housing area. there is about 0.1mm of space, maybe slightly more but not 0.2mm exactly (seems to be less than 0.2mm of space between the CPU BGA surface and the housing. I don't know if this is the same for LGA chips or not however. Anyway if you use the super 33+ tape + the dams, you decrease the amount of air that can get around the heatsink which is good.

    If the heatsink is perfectly flat and not convex and the pressure is semi decent (For BGA Garbage), then you can get by with just nail polish + dams.
     
    Last edited: Sep 18, 2018
    jclausius, Papusan and Mr. Fox like this.
  9. Mr. Fox

    Mr. Fox BGA Filth-Hating Elitist

    Reputations:
    31,618
    Messages:
    36,074
    Likes Received:
    58,769
    Trophy Points:
    931
    Liquid metal should improve the temps a little bit, but I think you may still have some thermal challenges with the single pipe heat sink and small radiator. It also appears none of the VRM chips or memory chips have any cooling.

    This is on all Clevo Pascal GPUs that I have seen. It is there to provide some protection for the surface-mounted components around the die.

    It is just a thin black plastic film. It is not rubber and has no elastic qualities to it.

    Yes, I agree. It's a nice idea, but it doesn't stick well enough to work and always seems to lift up around the die. That actually forms a pocket that is likely to trap liquid metal. If not for the fact that it doesn't stick well it would be nice to have.
     
    Papusan and Falkentyne like this.
  10. Mr. Fox

    Mr. Fox BGA Filth-Hating Elitist

    Reputations:
    31,618
    Messages:
    36,074
    Likes Received:
    58,769
    Trophy Points:
    931
    You can also use kneaded eraser to fill up the area around the CPU socket to keep liquid metal out, same as protecting against condensation on chilled systems. This is how I have my CPU socket on my desktop with the water chiller. You can set the foam dam on top of that. Just make sure the kneaded eraser is not taller than the IHS. It will squish down, but you don't want it between the heat sink and IHS because that will interfere with contact.

    [​IMG]
     
    Falkentyne and Papusan like this.

Share This Page