How do I properly lap my heatsink/waterblock?

[W1zzard]

Show article

 

[Mussels]

Nice guide, seems a pic or two is missing tho.

"[PIC of heatsink + ruler with light shining through]" but no pic, etc.

 

[JC316]

I am fixing to test on my stock heatsink before even THINKING about my freezer pro, but I have a question.

Cathar mentions rotating it 180 degrees, do you keep sanding in the same direction, or reverse? Example:

I am sanding in an upward motion and I need to rotate it 180 degrees, do I continue in an upward motion, or do I start in a downward motion? Thanks in advance.

 

[Ketxxx]

Follow the machine marks for the best possible finish. Dont go against them and just keep sanding until your happy with the finish. Be aware that if your sanding aluminium, depending on the quality of it, it can be difficult to get a mirror finish, in which case aiming for a very smooth feeling, flat finish, is the best option.

 

[Jonnycat]

I've always just done a "figure eight" pattern, with good (enough?) results.

 

[JC316]

Well, I laped my stock heatsink and I think it went rather well. It was HORRIBLE, the middle wasn't even touched for my first 5 minutes of sanding. With the water test, it was worse than the HS that was shown here. After I was done, it was perfectly flat and I could squeeze water out from all sides. Tomorrow, I am going to take my northbridge cooler off and lap it. Thanks for the replies and for this article, it really works great.

 

[Lazzer408]

Does anyone have before/after thermal results? How big IS the benifit? 2deg? 15deg?

 

[TLH]

Does anyone have before/after thermal results? How big IS the benifit? 2deg? 15deg?

Kinda depends on how bad it was in the first place and what it's going to sit on when you're done.
I lapped my Thermaltake Volcano 12 that sat on a xp3200 at the time and saw absolutely no difference whatsoever.It was pretty smooth though already and sitting on an Athlon XP's core is really tiny.
Mostly people report a couple of degrees C I think.

 

[JC316]

Does anyone have before/after thermal results? How big IS the benifit? 2deg? 15deg?

Ok I have some numbers for you. My Northbridge temps were

34*C Idle - 48*C Load. This was before lapping

Now they are 24*C idle - 36*C load after lapping and silver compound.

This was a bad case though. The cooler was visibly lopsided and the "thermal" material was teh consistinsy of frozen bubble gum.

 

[vipercrazy]

both the xbox 360 HS's could use a major lapping
the gpu specifically, its some crappy metal and it looks like it came strait out of the ground

 

[Coolyou]

Great article.. I would have written one myself, but never had the time to!

Also take a gander at this article! I had never laughed so much in my life...
http://hubpages.com/hub/How-to-destroy-your-CPU-by-lapping-it

 

[KBD]

i thought CPUs could be lapped.


silly article though

 

[sneekypeet]

i thought CPUs could be lapped.


silly article though

They can be ...it just goes to show that any ass with an opinion can try to sway the masses. aslo anyone claiming 20*C drop in temps was wrong to begin with. I personally have done many CPU's and got good results with each. Of course the older hardwae is where it mattered most

 

[KBD]

They can be ...it just goes to show that any ass with an opinion can try to sway the masses. aslo anyone claiming 20*C drop in temps was wrong to begin with. I personally have done many CPU's and got good results with each. Of course the older hardwae is where it mattered most

thats why said the article is silly. I did lap my heatsink but i was afraid to touch the CPU, i was worried that the dust may get to the CPU sensitive areas and i didnt see any CPU lapping guides, perhaps its time for one on TPU?

 

[sneekypeet]

Same process of the blocks really!

I use straight tap water and wet/dry sand paper...the biggest issue I had was being careful on the 939's not to kill the pins!

 

[KBD]

Same process of the blocks really!

I use straight tap water and wet/dry sand paper...the biggest issue I had was being careful on the 939's not to kill the pins!

how do you know when to stop lapping, i mean with HSF its obvious, mirror finish, but with CPU i wouldnt want to lap it to death. And does it even make sense with 775/AM2/AM2+ CPUs?

 

[sneekypeet]

how do you know when to stop lapping, i mean with HSF its obvious, mirror finish, but with CPU i wouldnt want to lap it to death. And does it even make sense with 775/AM2/AM2+ CPUs?

its like 2-5*C at most. You will know. the inside is copper and when you start it off it is nickle (IIRC) plated. as you sand you remove the plating and expose the inner metal. you will see as long as the table/piece of glass/ rock countertop is level and flat, that it will come off the edges first usually. I went untill it was all copper at like 800 grit, you may want to start lower, then I just progressed with grits until i reached 2000 and 95% of the scratches were gone. Polishing is up to you, I do use neverdull to shine it up, then just clean with 90% alcohol then install. you can only screw it up if you push to hard while sanding or are using an unlevel surface to sand on.

Pull out a razor blade and cheeck its level-ness in all directions( top to bottom, side to side, and corner to corner) if you dont see light Id leave it, but again its a few hour process if done correctly. so ita a time over gain type of thing.

I lapped all my previous CPU's that stayed in my rig....this E7200 its the first in a while I havent lapped!

 

[panchoman]

most of the time instinct will tell you when to stop, you want to sand down the nickel plating on top untill you get to the main copper part of the ihs. sand the copper untill its completely flat (a razor blade is a good tool to use for this). also some people like to wet sand with mineral oil in order to minimize the risk of ESD due to friction and frying from using water to wet sand.

lapping causes about a 2-5C difference in temps most of the time btw.

 

[KBD]

very helpful, thnx guys. I'll definately consider lapping a CPU when upgrade in a month or so.

 

[panchoman]

http://forums.techpowerup.com/showthread.php?t=32771

thats a good thread to take a look at man.

 

[KBD]

http://forums.techpowerup.com/showthread.php?t=32771

thats a good thread to take a look at man.

great, nice find

 

[Coolyou]

how do you know when to stop lapping, i mean with HSF its obvious, mirror finish, but with CPU i wouldnt want to lap it to death. And does it even make sense with 775/AM2/AM2+ CPUs?

Just as sneekypeet stated. However, before you begin it's proper run a razorblade along the top to see if it actually needs to be lapped (nickel-copper alloy conducts, a pure copper base isn't necessary). If it does then mark an X over the nickel plating with a permanent marker. You mark the processor each time you sand it down, until perfectly flat (not mirror finish). This helps guide you to a flat finish, lapping is about a FLAT surface (removing those minute dimples on the surface) not how SHINY.

Water and a small amount of detergent (SMALL AMOUNTS!) is used to help with the metal flakes. Typical and safe process would to sand then clean (cleaning residue on the processor with a dry cloth and rubbing alcohol facing down and washing the sandpaper of excess materials), sand and clean, repeating. You don't lap the processor in one stroke.

As for worrying about the base/pins, would be safe to use the plastic shield which came with the CPU.


Edit:
Forgot to mention... the best place to find this Grit of sandpaper is at a AutoPaint dealer (UnitedAuto B&M or http://www.nortonautomotive.com/), normal car parts stores do not carry this fine of grit. 2000 grit isn't necessary.

 

[KBD]

thanks

after i lapped my heatsink my temps dropped about 5 C load which i suppose was worth the effort. As others said i should expect additional 2-5C drop if i lap the CPU.