How to spread AS5 on concave/convex heatsinks

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This is the bane of my life. My TRUE (thermalright ultra 120 extreme) is convex, my cpu the opposite. Following AS's instructions doesn't help. I found that spreading a thin line of paste across the heatspreader caused the paste in the middle to spread out so much that there was very little in the middle. The old method of putting a blob in the middle was slightly better but then all 4 cores are not covered. Cores idling at 46 degrees and that's after lapping the heatspreader (previously 50). This is at stock everything.

I am now thinking of following Thermrights instructions...spread a thin layer of paste on the heatspreader and another thin layer on the base of the heatsink. I know more paste is not better, but won't these 2 layers of paste help fill the gap that is quite obviously there between the heatsink and heatspreader. What do you reckon, and is the stuff that comes with the Thermalright any good ?

This is the 2nd TRUE I am on now.....and if this doesn't work I am rmaing both of these pieces of junk and buying a Noctua.

Incidentally does the non extreme 120 have issues with poor surface conact. I know it doesn't have the stupid problem with the heatsink rotating.
 
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My extreme-120 didn't have this problem so its sounds like you've just been unlucky with yours.

As you said having too much heatpaste is generally not good, but it must be better than having air. I'd just give it a go and see what happens.
 
The corners don't really need to be covered...

Normally I'm left with a circle in the middle of the IHS and little in the corners.

EDIT: I'm not generally keen on lapping IHSes but you could lap the cooler to make it more flat - nothing to lose really.
 
The instructions on the Thermalright website you're referring to, do you mean rubbing the paste into the heatsink and CPU's IHS with a plastic bag over your finger? If not, then i'd probably try this method because, after rubbing the paste into the surface of both items, you can then do the normal "line" method, suggested by Arctic Silver, and see if it yields an improvement.
 
Yes...the good old rubbing paste with a sambo bag or one of those fan screw bags!! I remember with the original AS it was to fill the micrscopic peaks and valleys in the heatsink, and then you wipe away excess paste so there is just a haze there but the imperfections are still filled in.

However, what TR are talking about is actually applying the paste to the heatsink and cpu core using a thin layer. Clearly my problem is when the heatsink attaches to the core it's not making proper contact in the middle. I end up with paste everywhere it should be, but very little in the centre using the AS5 method, hence the idea to follow TR's instructions and put paste on both.
 
Yeah, i suppose TR's method would make sense in your situation. So, when you take the heatsink off the CPU, can you see that there's not much thermal paste in the middle? This might not be so bad. Doesn't it just mean that there's good contact between the IHS and heatsink in this area and, around the outside, there's not so good contact which is why all the thermal paste ends up there. I would've thought the temperature would be improved by the lack of thermal paste you see in the centre of the CPU's IHS since the heat doesn't have the extra thermal paste to travel through; instead, it just travels straight from the CPU to the heatsink.
 
I will try a think layer allround tommorrow and see what happens.

So I think maybe the heatsink is higher in the middle, this would explain why the paste gets spread out so. But why is there very little paste in the centre of the heatsink or cpu ?
 
By higher, do you mean the heatsink is convex? If so, then it would mean there would be less of a gap between the center of the CPU's IHS and the heatsink since they'd be touching. However, by them touching and the fact that the heatsink is convex, the less-important area toward the outer edges of the heatsink wouldn't be touching the IHS.
 
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