Shim soldering

So, I'm thinking about shimming the northbridge on my heatsink since I think the pad on it is getting a bit nackered from me changing paste.

My main theory is that instead of having to paste both sides and hen hope it stays in place and doesn't have bubbles, why not just solder it to the heatsink? All the rest of the heatsink is soldered together and solder will have a much lower resistance than even paste, let alone pads. What I was proposing doing was to simply get some low viscosity solder paste, apply the shim to the heatsink like any other part (except using solder paste), and then clamp it down for a minute or so to make sure the paste has spread all over. Then all I'd need to do is use a heat gun and then the shim would be well and truely attatched to the heatsink.

Has anyone tried anything like this before or am I on my own? I've been thinking about getting a new heatsink for a while since this one seems to have some pretty stuborn dust in it which I can't get out. If the worst comes to the worst then I can always buy a new one.


PS: I've heard that unlike other thermal pastes, the "less is more" approach doesn't apply so much to MX-3, which is what I'm using. I've always tried to se the least paste possible and every time it's been pretty much perfect application as far as normal pastes would be concerned. Is this just a rumour or is there some truth to it which could explain my slightly higher temps?

 

If I remember right, the little tab that stick out from the CPU part of the heatsink assembly to "cool" the chipset is aluminum on the bottom where the factory foam pad sits... Not sure how your going to get solder to stick to aluminum

Also, the chipset only dissipates about 4.5 watts. It is actually being heated by the stock "cooling" solution during high cpu loads because the temp rise of the heatsink is higher than the temp rise of the chipset die. I wish there was a way to fasten a discrete heatsink on the chipset and just chop off the tab from the main heatsink, but there is only 1 screw.

EDIT: If the bottom of the heatsink where it covers the chipset has a copper insert, your idea of soldering it on could work. I would be worried about overheating the heatsink during this soldering though because you don't want to overheat the heatpipe depending on its internal construction. If it uses a cheap nylon wick inside, you could melt it and ruin the heatpipe if heated to the temps needed for solder wetting to occur.

 

They solder the whole thing together so I don't see any reason why it would ruin the heasink. The only possible way I could see is that they put the stuff in the heat pipe after they solder it all together meaning that they can keep it all cool.