what is lapping?

I've read it here but i don't know what it is. How do i do it to my dual fan p3 slot 1 HS?

Sanding. Use water sanding paper. I haven't done any lapping, so I can't give any more detailed instructions. Hopefully someone else answers too.

Lapping is sanding the heatsink and sometimes the cpu...although you need to be very careful with the cpu...

Get yourself some 600-800 grit sandpaper, and some 1000 grit to finish it off with...also, do it on a piece of glass or mirror for an even sanding job.
When I did my hs & celly, I used wet sandpaper...

Fix the sandpaper (start with the grittier of the paper) to the glass, wet it, then sand your hs in a figure 8 motion occasionally do an up & down and side to side motion...with even pressure...when you have evened the surface out polish it off with the 1000 grit ensuring that there aren't any scratches or dimples anywhere on the heatsink.

read the front page..they have in depth articles on the subject I'm sure

compuwife (Apr 26, 2001 01:58 a.m.):
Lapping is sanding the heatsink and sometimes the cpu...although you need to be very careful with the cpu...

Get yourself some 600-800 grit sandpaper, and some 1000 grit to finish it off with...also, do it on a piece of glass or mirror for an even sanding job.
When I did my hs & celly, I used wet sandpaper...

Fix the sandpaper (start with the grittier of the paper) to the glass, wet it, then sand your hs in a figure 8 motion occasionally do an up & down and side to side motion...with even pressure...when you have evened the surface out polish it off with the 1000 grit ensuring that there aren't any scratches or dimples anywhere on the heatsink.

read the front page..they have in depth articles on the subject I'm sure

Click to expand...

Thanks Compuwife,

Actually I did read the front section before I posted and I didn't find anything substansive about lapping. Maybe I wasn't looking in the right place.

I will try doing what you said with the wet sand.

If you want to go the extra mile also use 1500 and 2000 grit. For CPUs, 2000 is all I use.

Another trick is to do the final lap with a fresh sheet of 2000 grit using Artic Silver as the lube. This puts a mixture of silver, aluminum and abrasive residue in the microscopic surface imperfections of your HS instead of just aluminum and abrasive residue.

someone also mentioned somewhere around here about using toothpaste for a good polish.

Why leave toothpaste residue where you could have a good thermal compound?

you mention that you can lap the cpu?? where exactly would i sand paper my amd socket A cpu?? also, is it safe to work under wet conditions (you mention water) when sanding the cpu??

I have wet sanded my Birds with 2000 grit. It’s a tedious process, 20 second interval results are examined with a 20 power loop. I lap until the CPU is flat and no markings are visible. If you see copper your CPU is toast. Not for the faint at heart. I have been called crazy for doing this but have achieved good results. Bare in mind if you have a marginal CPU that passed AMD’s standards it could die before you get it to the level I describe. PROCEDE at your own risk.

There has also been some talk about Athlons becoming convex at high temps and pumping the thermal compound out during the heat cycles. I can’t verify this but it may be a factor.

the crest part is here:


As far as leaving a residue, considering all but the grit is water saulable I'd think it's an excellent choice. Sure you can go to the microscopic level, but what do you think SANDpaper leaves? Besides that, someone made a good point that toothpaste breaks down. In other words, the more you rub, the smaller the abrasive becomes.

Shame on you Collin! =)

Actually I can understand what he's saying tho, but I don't think he takes into consideration what ANY compound will leave behind. You can do a final "shot" with AS and leave silver behind, but no matter what you use you're going to leave something behind. and keep in mind as is 98 or 99 percent silver......that leaves a percent or two for "other" as well as what is attached to the sand paper.

I think "extreme lapping" could get really crazy. Look at the guys using liquid nitrogen to "extreme cool". Truth is, sanding with 1000 grit and quitting......or sanding with 1500 or even 2000 grit and quitting may only gain you 1c or maybe 2c......not worth micro dynamics. If you're not trying to get from 1304 to 1305 mhz........don't worry about it.