about polishing heatsinks...

[eggman21]

i don't have no sandpaper. how do i polish heatsinks without anysandpaper? is there's a way?

 

[Yogi2367]

Lapping and water sanding are two way different processes. First of all I'm not at all certain why you would want to introduce water to a CPU. There's no guarantee it's even water-resistant, let alone waterproof. Lapping, like you would do to the intake and exhaust valves in an engine head uses lapping paste. Something more akin to jeweller's rouge would be more appropriate for a CPU. You simply put a dollop or two of the rouge on a flat block of steel, preferably stainless and a couple inches thick, and swirl it under light pressure until you get the desired effect (affect?). You would use the same process with a heat sink. When it's all done you simply clean off the lapped piece(s) with 99% alcohol.

Heat sink, not cpu...

I'm not a machinist like Susquehannock (kudos on the AMD polish), but I am an engine builder. Certainly doesn't qualify me as an expert, but I do know the difference between smooth and rough, and flat and uneven, surfaces.
You're saying heat sink, not CPU. If you're not going to do both the CPU and the heat sink, why bother doing either one? I get it that the more polished surface of the heat sink offers the idea that there is potentially better contact with the CPU, but, if the heat sink and the CPU are not matched/mated, then you still have to use thermal paste to make up for the dissimilar planes you have now potentially introduced. You're quite possibly no further ahead than if you had just left it alone in the first place.

 

[13thmonkey]

In the days where the heat sink connected to the raw chip I think you could believe it to be flat enough to make a difference. Where you have a heat spreader then I agree, and indeed there were people who would polish both the HS and the heat spreader on the CPU until copper showed through.

 

[Susquehannock]

Speaking of the old raw chip days. Came across a few extreme close-ups of naked AMD Thoroughbred cores when looking for my lapping images above. Not smooth as we thought.

>> http://i.imgur.com/slqxY37.jpg
>> http://i.imgur.com/2eHzmSO.jpg

 

[13thmonkey]

they had QR codes in those days? Any idea of the scale of those imperfections?

 

[Susquehannock]

They have been around since the early 90s. Never thought about what the little square was until a member in one of the extreme overclocking forums posted those images. Cannot remember the magnification as it was 12 years ago.