What methods do you use to lap your stuff?

[mazakman]

I found this article today. I thought it was a good basic guide, and I like the idea of using a marker to see how even the surface is. The definitely are against using circular motions, though.

 

Nice find!

 

I agree with the part about "moving the heatsink gently against a flat abrasive surface" and not because it may tear the sandpaper, but personally I prefer the figure 8 motion over back and forth. Excessive force will only lead to fatigue in the muscles of your hand and arm that is holding the part. Once fatigue (pain) has set in keeping the part in the same plane (or flat if you prefer) as you are lapping becomes excessively difficult so final results will suffer.

 

A figure 8 is 2 circular motions in contradiction to each other. The first in a clockwise direction and the following in a counter-clockwise direction so it's not like going around in circles in the same direction all the time which is alright if flatness is of no concern and all you want is a shiny finish.

 

For true flatness across a complete surface the figure 8 motion does work out better, that's how I was taught to lap in the industry. But then again there aren't any design engineers around demanding a maximum of 0.0002" flatness across the complete surface of the heatsink so imperfections at the very edge can be tolerated here.

 

At the very least please try both methods and see which is best suited to your needs.

 

chavalcito, have you attempted to lap anything yet? Do you have any old heatsinks laying around that you could use for a trial run?

[kendellrt]

I lapped an old Tt Volcano 7 for an AXP. I got a nice shiny surface, and under the advice at the time, I used a figure eight. I didn't get that great of a result, though. I was more uneducated in the subject at the time, and I don't think that my lapping surface was sufficient.

 

I have heard people say to use a plate of tempered glass, would a thick piece of plexi work? I guess I could get either at a local Lowe's or Home Depot.

 

What do you think of using oil? Would you recommend that over H2O and some dish soap?

[graysky]

Oil will work but beware of using anything too heavy like motor or cooking oil; you want something with a low boiling point. The best lubricant you can use is low odor kerosene you can get at any store that sells camping gear. Failing that, mildly soaps water will be just fine (like 1 drop of dish soap in 1 liter of water).

[kendellrt]

Oil will work but beware of using anything too heavy like motor or cooking oil; you want something with a low boiling point. The best lubricant you can use is low odor kerosene you can get at any store that sells camping gear. Failing that, mildly soaps water will be just fine (like 1 drop of dish soap in 1 liter of water).

 

What about Mineral Oil?

[kendellrt]

I just read a guide, from a link that was posted on graysky's results post over at XS. This guy suggested starting out with really low grit, like 220, and using a circular motion at first. The circular motion was just to get the nickle off. After that he used the same method as nrg recommended, but said he did not use any liquid at all. I figure I will use a drop of soap in a liter bottle, as graysky recommended, but what do you guys think of circular motions with a very coarse grit just to get rid of the nickle plate?

 

Also, when I do my Zalman 9500, what would be the best way to grip it while lapping? It's pretty top heavy and I don't want it to be uneven or bend the fins. It has an awesome mirror finish, but I thought maybe I would see if it is flat by drawing an X across is and using some 1600 or 2000 grit paper to check if it polishes evenly.

[graysky]

What about Mineral Oil?

 

Too heavy dude... you'll have a hell of a time getting rid of it. I'd either use low odor kerosene or that soap/water mix.

 

I just read a guide, from a link that was posted on graysky's results post over at XS. This guy suggested starting out with really low grit, like 220, and using a circular motion at first. The circular motion was just to get the nickle off. After that he used the same method as nrg recommended, but said he did not use any liquid at all. I figure I will use a drop of soap in a liter bottle, as graysky recommended, but what do you guys think of circular motions with a very coarse grit just to get rid of the nickle plate?

 

Also, when I do my Zalman 9500, what would be the best way to grip it while lapping? It's pretty top heavy and I don't want it to be uneven or bend the fins. It has an awesome mirror finish, but I thought maybe I would see if it is flat by drawing an X across is and using some 1600 or 2000 grit paper to check if it polishes evenly.

 

I didn't do circles with mine at all thinking uneven pressure would ruin it. I also did the whole thing wet; it lubricates as well as catches metal particles/dust you don't want in your hardware or in your lungs.

 

The Zalman 9500 is mirror finished??? Hmmm... that may imply that it's flat but your idea to use a marker "X" and 1600 grit is a good one. As to grip, just do what gives you the most control over it. Don't let it bounce or jump as you move it across the sandpaper.

Edited July 6, 2007 by graysky

[kendellrt]

Too heavy dude... you'll have a hell of a time getting rid of it. I'd either use low odor kerosene or that soap/water mix.

I didn't do circles with mine at all thinking uneven pressure would ruin it. I also did the whole thing wet; it lubricates as well as catches metal particles/dust you don't want in your hardware or in your lungs.

 

The Zalman 9500 is mirror finished??? Hmmm... that may imply that it's flat but your idea to use a marker "X" and 1600 grit is a good one. As to grip, just do what gives you the most control over it. Don't let it bounce or jump as you move it across the sandpaper.

I am going to Home Depot tomorrow, hopefully all goes well. Seriously though, I could shave on the bottom of my Zalman 9500. That doesn't mean it is flat, though!

 

Thanks for the help.

[graysky]

Also plan to stop by an auto parts store... doubtful that you'll find any wet/dry over 600-800 grit at HD. I got my 800 and 1000 at an auto parts store.

[kendellrt]

Also plan to stop by an auto parts store... doubtful that you'll find any wet/dry over 600-800 grit at HD. I got my 800 and 1000 at an auto parts store.

 

Thanks

[OneShot 926]

On my way to the auto parts store.

[road-runner]

@road-runner: the only way to know for sure if your CPU is flat is unfortunately to lap it. You'll know after about 20 seconds because you'll start to see the material come off the higher parts first like this:

I think I will do mine tomorrow, I looked for piece of glass and could not find it earlier. I will look again tomorrow I know I have one from when I done my old maze 4...

[kendellrt]

I think I will do mine tomorrow, I looked for piece of glass and could not find it earlier. I will look again tomorrow I know I have one from when I done my old maze 4...

That is a good question - where do you find a flat piece of glass? How big/thick should it be, and how much do you think it will cost?