Lapping one's CPU and HSF is old-hat for many folks around here, it produces the kind of "oooh! shiny!" pictures and eye-candy appeal that makes it fun and rewarding to do (not too mention that it does happen to lower your operating temperatures as well, purely an unintended consequence of the lapping process
).
I was bitten by the gottalappit bug long ago and it was just a matter of time before I'd be putting my FX-8350 onto the sandpaper.
Now these preliminary results are from the 8350 and the stock HSF, but I have a handful of other coolers that are also lapped and will be tested (and results will be reported in this thread) in time as well.
First up though are the results with the AMD stock HSF...I have to say this little HSF is just amazing at how good of a job it does for something that came with the CPU. Puts every other stock air HSF to shame!
All right then, how about some pretty pics
First up - the sandpaper portfolio. I like to use sheet-sized (8.5x11) sandpaper when possible as it gives me lots of room to move around without over-loading the paper with metal. The sandpaper I use can be bought at any auto-parts dealer (A1 Auto, Autozone, etc).
I use six different grits ranging from 220 to 3000. Anything above 800 is really just for putting a mirror finish on the surface and isn't expected to improve temperatures. (remember lapping is done to make the surface flat, not necessary to make it polished smooth)
I lay out one of each sheet and tape them down to the surface of a plate glass desktop.
To reduce the loading effect on the sandpaper, I wet-sand with 220 and 400 grits and dry-sand with the remaining grits (800-3000).
Sanding is done as straight strokes, out and back, 10 times and then rotate 90 degrees. This is done a minimum of 8 times per grit (resulting in 2 full rotations of the IHS and HSF during sanding).
Here are the unsuspecting victims, lazing about not realizing their world is about to get a little flatter
(I had a couple 3770k's I wanted to lap at the same time, batch-job style
)
A few passes on 220 grit is all it takes to get a feel for how warped the IHS or HSF surfaces were initially. If you see copper in the middle while the perimeter is still covered in nickel then you know the IHS was originally convex (like a dome), whereas if you see copper along the perimeter (edges) and nickel remaining in the center of the IHS then you know the IHS was originally concave (like a bowl).
Both 3770k's were concave, the one on the far right was oddly concave in that the bowl was most distinctly square and not a rounded by any means. The FX-8350 was the exact opposite, having a high center because it was convex.
Finishing up with the 220 grit, we have removed all the nickel and are looking at what basically appears to be "brushed copper". It took forever and a day to get through all the nickel on the FX-8350.
It was painfully slow enough that I contemplated going to 60 grit just to speed up the process, in the end I opted to just stick it out with the 220 grit. And an hour later you have the image above. :|
I was bitten by the gottalappit bug long ago and it was just a matter of time before I'd be putting my FX-8350 onto the sandpaper.
Now these preliminary results are from the 8350 and the stock HSF, but I have a handful of other coolers that are also lapped and will be tested (and results will be reported in this thread) in time as well.
First up though are the results with the AMD stock HSF...I have to say this little HSF is just amazing at how good of a job it does for something that came with the CPU. Puts every other stock air HSF to shame!
All right then, how about some pretty pics
First up - the sandpaper portfolio. I like to use sheet-sized (8.5x11) sandpaper when possible as it gives me lots of room to move around without over-loading the paper with metal. The sandpaper I use can be bought at any auto-parts dealer (A1 Auto, Autozone, etc).
I use six different grits ranging from 220 to 3000. Anything above 800 is really just for putting a mirror finish on the surface and isn't expected to improve temperatures. (remember lapping is done to make the surface flat, not necessary to make it polished smooth)

I lay out one of each sheet and tape them down to the surface of a plate glass desktop.

To reduce the loading effect on the sandpaper, I wet-sand with 220 and 400 grits and dry-sand with the remaining grits (800-3000).
Sanding is done as straight strokes, out and back, 10 times and then rotate 90 degrees. This is done a minimum of 8 times per grit (resulting in 2 full rotations of the IHS and HSF during sanding).
Here are the unsuspecting victims, lazing about not realizing their world is about to get a little flatter

(I had a couple 3770k's I wanted to lap at the same time, batch-job style
A few passes on 220 grit is all it takes to get a feel for how warped the IHS or HSF surfaces were initially. If you see copper in the middle while the perimeter is still covered in nickel then you know the IHS was originally convex (like a dome), whereas if you see copper along the perimeter (edges) and nickel remaining in the center of the IHS then you know the IHS was originally concave (like a bowl).

Both 3770k's were concave, the one on the far right was oddly concave in that the bowl was most distinctly square and not a rounded by any means. The FX-8350 was the exact opposite, having a high center because it was convex.

Finishing up with the 220 grit, we have removed all the nickel and are looking at what basically appears to be "brushed copper". It took forever and a day to get through all the nickel on the FX-8350.
It was painfully slow enough that I contemplated going to 60 grit just to speed up the process, in the end I opted to just stick it out with the 220 grit. And an hour later you have the image above. :|