Heatsink Lapping!! Anybody has a link?

[MeJa]

I want to do it to my waterblock just want to make sure on what sand papers to use. Anyone has a link?

[Thelemac]

Courtesy of dimmreaper:

Jeff’s Heatsink Lapping Guide:

What overclocking site would be complete without a lapping guide? So I compiled this short how-to for those who haven’t read about lapping before.

Lap is an old English word for polish. The Idea behind heatsink lapping is that the base of all heatsinks will have minor imperfections from the machining process. These imperfections limit the amount of contact there is between the heatsink base and the CPU. <b>Isn’t that what thermal compound is for?</b> Well, yes it is. But having the metal touch the CPU is far more effective. Unfortunately, because of the limitations of modern science, you will still have to use a small amount of thermal compound. You have to do this because even with 12000 grit abrasives, there will still be minor imperfections, without thermal compound these imperfections become air pockets. Air does not conduct heat very well, so naturally this is a problem.

The process of lapping it self is fairly simple. First thing that you will need is a very flat surface. I use an old scrap of aluminum. Many folks have been known to use a piece of glass. It doesn’t really matter what you use, so long as it is very very meticulously flat. Next thing you will need is various ratings of sandpaper. I usually use 200, 600, and 800 grit. The higher the grit rating, the finer the paper is. I like wet/dry sandpaper best, as it holds up for many lapping sessions.

Here is were I get around to the actual step by step stuff. Place the lowest grit sandpaper, abrasive side up, on top of your flat surface. Place your heatsink, base down, on to of the sandpaper. There are two common ways to move the heatsink. One is the circular pattern; the other is the figure eight pattern. I’ve tried both patters, and have not noticed any difference. I usually use the circular pattern, as it’s less strenuous. Lift the heatsink from the sandpaper from time to time, you will notice “high spots”. Keep sanding with the low grit paper until they disappear. After you have sanded away the “high spots”, replace the sandpaper with the next highest grit. Sand with this paper until all the rough scratches left from the last paper are replaced with finer scratches. After the rough scratches are removed, replace the sandpaper with your finest grit. Sand with this paper until all of the fine scratches left from the last paper are replaced with a gray satin finish. Replace the sandpaper with your rag now, and dump some buffing compound on it. Come on now; don’t be afraid to waste a little. That’s better. Now move the heatsink around for a painful extent of time. Pick the heatsink up. What’s that, still a few imperfections? Keep going then. I know your arm hurts, but trust me, it will be worth it. Now the base is nice and shiny, but still not a mirror. Go clean it up with rubbing alcohol.

[Kendan]

Here is a pretty good article. Check around and you will find more. but this is a good start. hope this helps. http://www.atlantaoc.com/reviews.php?op=showcontent&id=6

[MeJa]

Thx alot guys i'll be stopping by Homedepot on my way back from work ;) i'll let you guys know how did it come out ;)

Thanks again...

[Thelemac]

Originally posted by MeJa
Thx alot guys i'll be stopping by Homedepot on my way back from work ;) i'll let you guys know how did it come out ;)

Thanks again...

You'll have to go to an autoparts store to get above 600 grit (maybe 800, don't remember which)

[MeJa]

Oh ok!
Will do as a matter of fact there's a Discount Autoparts in the same shopping center where the Homedepot is ;)

Thanks for telling me!

[Patchmaster]

Contrary to what those instructions say, I strongly recommend against using rubbing or buffing compound on the heat sink. Any oil or buffing compound you put on the heat sink will get into those microscopic imperfections and you'll never get it out. You want thermal compound in there, not buffing compound.

If you fee compelled to clean the heat sink after sanding, use acetone or 91% isopropyl alcohol (NOT rubbing alcohol!) and give it plenty of time to evaporate.

When you're done lapping, get a disposable latex glove (or a plastic bag) and put it on your hand. Put a bit of thermal compound on the heat sink and rub it in real good. You should have almost no visible thermal compound on the heat sink when you're done. Then put a thin layer of thermal compound on the CPU. Probably wouldn't hurt to rub this in a bit too before you level it out with a knife edge or razor blade. Clamp the two together and you're ready to go.