HeatSink Laping

Has anybody here done this?
Is so what did you do?

[JavaDog]

Pretty simple actually. Get some 400grit, 800grit and 1000grit sandpaper. You will use 4-5 sheets of each. Some like to continue with 1500grit and 2000grit - you can if you like - but it shouldn't make any difference in temps.

Get a nice flat surface, if you have some surfaced aluminum or you can use a good counter-top or marble if you have it. Basically looking for as flat of a surface as you can get. Attach your sandpaper sheet to the flat surface (tape?) and with light pressure (and keeping the heatsink flat - don't tip it!) work in slow circles. When the surface of the heatsink looks uniform, move to the next grit (400 -> 800 -> 1000 and so on). DO NOT USE POLISHING COMPOUND - it will affect the performance of the heatsink.

All there is to it! Post some pictures when you get it done!

EDIT: Forgot to mention, a lot of people like the wet-sand too.

Originally Posted by JavaDog Pretty simple actually. Get some 400grit, 800grit and 1000grit sandpaper. You will use 4-5 sheets of each. Some like to continue with 1500grit and 2000grit - you can if you like - but it shouldn't make any difference in temps. Get a nice flat surface, if you have some surfaced aluminum or you can use a good counter-top or marble if you have it. Basically looking for as flat of a surface as you can get. Attach your sandpaper sheet to the flat surface (tape?) and with light pressure (and keeping the heatsink flat - don't tip it!) work in slow circles. When the surface of the heatsink looks uniform, move to the next grit (400 -> 800 -> 1000 and so on). DO NOT USE POLISHING COMPOUND - it will affect the performance of the heatsink. All there is to it! Post some pictures when you get it done! EDIT: Forgot to mention, a lot of people like the wet-sand too.

thanks.

[JavaDog]

Originally Posted by WallCrawler thanks.

No problem, hope it comes out nice!

[JFettig]

circles arent good, linear motion is what you want, circles will create a convex surface.

start at 220, make sure to wet the paper, soak it preferably in soapy solution, this solution will cause the paper to stick to the flat surface(I use a ground granite plate)
lap the heatsink with its own pressure(maybe a little more) forward and backward in a linear motion, you can rotate it a few times while lapping.

you can(if you want to check it) mark the bottom with a sharpie marker then lap it some more and see where its not so flat, then move up to 600grit and stop there.

Jon

[ViperTX]

Does this really make a difference??

[CNCadmin]

Originally Posted by ViperTX Does this really make a difference??

Maybe on a sub atomic level, but I doubt you will see it, unless you ran temp test at the core. It's like running high octane fuel in your car instead of regular, you feel like your engine runs better, so yes you will feel like it's making a difference.

[ViperTX]

I am thinking this is something "ger" would really get into the analysis of the difference! Did you see his analysis on the "surface finish" problem....pretty amazing...it's something that NASA at one time was capable of doing!

[CNCadmin]

Originally Posted by ViperTX I am thinking this is something "ger" would really get into the analysis of the difference! Did you see his analysis on the "surface finish" problem....pretty amazing...it's something that NASA at one time was capable of doing!

Surface finish is very import on a microscopic level, but grease and water cooling can easily IMO give you just as good result, again unless you have the equipment to measure you would never know if you had a cooler CPU even by than you maybe got it 2% cooler.

[JFettig]

Viper, depending on how much lapping it really takes, it can. or if the heatsink is concave as is, circular motion would actually speed up lapping a little then to go to linear. The flatness does help a ton because it will cause the heatsink and core of the cpu to mate better and increase heat transfer. You can actually carefully lap a cpu and heatsink together(not recommended) to get the best transfer, but its likely to screw something up.

Jon

[JavaDog]

Sorry, but I (and most other modders out there) disagree about linear versus small circles when lapping. I have always used small circles and I can get a nice mirror finish in my blocks. Again, I also recommend starting with 400 grit and not anything coarser...

Lapping a heatsink is all about getting a "smoother" finish than the way they ship. Some heatsinks have a very poor finish, other are lapped at the facotry - depends on who you buy. You want a good surface for your paste, whether you are using Arctic Silver or just basic "white goo". I have seen a properly lapped HSF drop temp by 2*-3* after lapping. Might not be much, but if you are overclocking it might mean the difference between stable and not.

[JFettig]

Javadog, I have been in watercooling for over 3 years now, have made around 50 waterblocks, lapped many more. Check around ocforums,ocau,procooling etc.

A mirror finish means NOTHING, I can get a mirror finish by hand sanding the base of the thing.

Ron, what heatsink do you have that you want to lap? if its a swiftech, thermalright, or any of those better ones, DO NOT lap it, you wont gain anything.

Jon