GUIDE: Lapping

Grantofhell

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Again, I guide I see is not on our computer related forums. ArrizX or a mod, please put this one in our Reference/Guide section as it probably doesn't belong on the main hardware page.

THIS WILL VOID THE WARRANTY ON YOUR PROCESSOR!

This is quick and simple guide to explain what lapping is and how it can be useful to you.

First off - Lapping. But this guide will instruct you how to hand-lap your processor, heatsink, or any other device with a necessary contact.

Necessary Items -
  • A Flat Surface - A lot of people say "only use glass!". But honestly, you can use a table top if you want. As long as the surface is flat and level.
  • Lapping/Sanding Paper - Depends on how long you want to work. I'd suggest 220, 400, 600, 800, and 1000, and even 1500 in some cases. You could go with 2000 and 2500 if you want, but you might pay some pretty pennies.
  • Tape - Any kind will do, as long as it holds.
  • Marker - Preferably Sharpie.
  • Compressed Air - Helps you to make sure the processor/HS are clean when done.

*Side Notes*

Some people suggest to use something to keep the "pins" straight. If you're on S775 or the likes you should be fine as they don't have pins :p

Now that you've got all your materials, Start the project like this.

Take the Sharpie and draw an X on on the item, from corner to corner. This will help you to see how uneven your item really was and know when you've completely reached the copper in your IHS (Integrated Heat Spreader).

Next up, prepare your surface. Take the first paper, 220, and tape it down to your flat surface on all four corners.
Take your item, and run it over the sanding paper in a circular motion. Do this until all of the nickel coating is gone/worn away. Be sure to rotate your item by 90 degrees every 15 seconds to ensure even sanding.

Once all of the nickel is gone and you see bare copper, switch up to 400 grit. (by taping it down to you surface.) Again, the circular motion, occasionally turning the item by 90 degrees. Use 400 until some of the deeper scratches lighten up.

Proceed to 600 grit, At this point, you can start going vertically and horizontally switching between them every 15 seconds.

Do the above with 800, and 1000 until you are satisfied. You are also welcome to continue with 1500, 2000, and even 2500. Doing various movements to counteract the previous scratches. It doesn't have to have a mirror finish, that's just a nice touch. The point of lapping is to even out the surface of your item so that it makes MORE contact and transfers heat better. Also, you will need slightly less thermal compound applied to your item after it has been lapped; There are less microscopic gaps for the compound to fill!

Here's a little something I got done on one of my old P4 478's and it's heatsink. vvvv




:)


Suggestions? Comments? Additions? Corrections? Post it here.

~Grantofhell.
 

dude_56013

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I think it's important to note that lapping isn't to achieve a mirror finish (which you sort of note), but to take the deep grooves out the heat conductor on whatever you are working on so that you have more metal to metal contact, rather than metal -> TIM -> metal contact. It's also important to note, that after lapping correctly, you should NOT need to put as much TIM on as before you lapped, since obviously, you created a smoother surface with narrower ridges, therefore requiring less TIM to fill the voids.

In any case, a very good guide.

Also, just to add, you can wet sand your HSF is you want to. That's what I've done before with a lot of old "block style" HSFs from older machines. I'm sure you can do the same to newer HSFs as well. I wouldn't recommend wet sanding your CPU, though :p

BTW: To any mods or David; it sure would be nice to have a section devoted to guides. I think it would make finding them a lot easier. :)
 

Grantofhell

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Both. I lapped my old P478 on the nickel plate, and the stock HS that came with it. I'm currently lapping the proc down to the copper plate. Maybe even shoot for a semi-mirror finish.
 

Teny

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I need to find some friends who have some experience to help me do these type of things.
 

Grantofhell

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You have all of us here :) I've done a number of different mods. Not terribly good, but I have some experiences.
 

Teny

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Yeah, but it would be a lot better if there was someone there right near me so they can tell me what to do, when to stop, etc.
 
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