Thermal putty as a liquid metal barrier

[MindArlekin]

I ran my 4070ti with LM since December of 2024, runs fine, -10 degrees. I insulated capacitors around gpu die with nail polish.

Now I'm planning to swap my mobo to ITX and put my GPU vertically behind mobo, sandwich style. And with this comes the need to create a sort of insulation\barrier so if LM spills down, it will not short out other components.

I'm planning to use Kapton tape to insulate the edges of the GPU substrate and memory chips/SMDs around the GPU, and to create an actual barrier, I want to use thermal putty.

Is this plan of mine reasonable, or am I mistaken and missing something?

 

Thanks in advance.

[manikyath]

in theory as long as the thermal putty and liquid metal dont chemically interact at temperature it's fine? all you need is to essentially create a seal around where the LM sits. afaik the "production" way of keeping LM in place is a rubber gasket. you just want to make sure that it's not chemically interacting, and it's not interfering with mounting pressure.

[MindArlekin]

52 minutes ago, manikyath said:

afaik the "production" way of keeping LM in place is a rubber gasket

I considered using a foam gasket made from rubber or silicone, but the thinnest material that I found was 2 mm. I fear that I will have a hard time making a gasket (mainly because of potential need to layer those materials to make a gasket) that will be able to compress enough to not interfere with the GPU cooler contact with the die.

 

58 minutes ago, manikyath said:

thermal putty and liquid metal dont chemically interact

I believe that this is not a problem. Even if LM interacts with whatever material is used as a thermal conductor in a putty, it will still be trapped within the polymer mass, which makes putty a putty.

I'm not planning on dumping an overwhelming amount of LM, so I hope it will never leak, but if it leaks, it should be minor enough to be stopped or absorbed by putty without seeping through.

[MindArlekin]

I will be opening my GPU anyway, so I will take height measurements of the die before committing to putty or gasket way. If it is lower than 2 mm, I will go with a gasket.

But I bought putty ahead of time anyway, because it has implementations outside weird LM stuff.

[manikyath]

5 minutes ago, MindArlekin said:

so I hope it will never leak

afaik with vertical mounts it's not so much an "if" the LM will seep, its a fact that given enough time it'll run as far as it can manage, which is why sealing it in place is a requirement.

[MindArlekin]

Well, I will make an update after I get some measurements.