I mean, if you want to permanently glue your heat sink to your CPU, I guess it would do something.

Still don't know if anyone's tried it, but other people have had similar thoughts - https://arstechnica.com/civis/viewtopic.php?t=686917

Seems like the consensus is it might do a passable job but you will never be able to separate the heatsink/cpu (or whatever your specific usage is) again, safely.

thermal epoxy is usually used for fixing tiny heatsinks to VRM modules, RAM chips, etc.

Linus Tech Tips tried a thermal epoxy, and it was worse than even a graphite thermal pad.

kingcake wrote on 2020-07-15, 18:07:

JB weld is metal filled. Seems like it would conduct heat reasonably well.

Anyone tried it?

I have used JB Weld a lot, and JB Weld has failed a lot on me, even though I always go the extra mile and rough up the surface and clean with rubbing alcohol to remove any oil and dust/dirt, but when it works it seems to work well - until it just falls right off, the only thing I use JB Weld for now is when I have to fill in a hole, JB Weld will not work for heat sink compound, and the slick surfaces of the heat-sink and CPU will allow the JB Weld to just fall right off at some random later time.

Original J.B. Weld is a fix all export. Works great on plastics and metals.
There are others variants that work in high heat applications.

But for a CPU I would just get a nice heatsink and make your own clips to clip the heat sink to the CPU.
Its easy. You can even cut and bend a clip from a pentium heat sink to fit and clip on the the 486 CPU.

I've been curious to try JB Weld for this but never have. At one time I thought about doing an experiment with a bunch of "cheap" super-7 CPUs. That was back when they were worth $1.

I have used Arctic Silver thermal epoxy a couple of times. Once was to attach an AthlonXP heatsink to a P3-S 1.4GHz after I had broken the CPU socket. It's in a small Compaq Deskpro EN case. I have no idea how hot it gets but it never had any apparent heat problems (I used it daily for about a year). If you do that, pay attention to where the ZIF lever is so you don't block it.

The other was to attach a socket-7 heatsink to an Intel 875 chipset, whose contact area is a lot less. It never spent much time standing vertically but for whatever it's worth, it's definitely stuck on there. I weighted it down while it was curing.

Unfortunately I think the Arctic Silver product is discontinued.

One thing I did use JB Weld for was to repair a broken piece of plastic that bears stress on an mPGA478 heatsink. I trimmed down a plastic shroud from an IDE header and used it as a splint. I think it's stronger now than when it was new. The ones that haven't broken yet feel more fragile to me.

Had a total fail when I tried to JB Weld a kid's plastic "recorder" (musical instrument) from school. After setting for whatever long amount of time, it just pulled straight apart. I guess it needed to be compressed while curing, but I didn't have any good way of doing that.

There is a "5 minute" version of JB Weld but personally I don't have as much faith in it. The slow-setting stuff is probably stronger.

JB Weld pretty much sucks. I haven't bought it in years because when I used to use it, it would fail pretty quickly.

My guess is that it would fail really quickly in an application that has lots of thermal cycling due to the different thermal expansion and contraction properties of the different materials.

Thermal epoxy is what you want.