xp-120 lapping revisited

R

ryuji

2[H]4U
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Jun 11, 2004
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gave my old lapped xp-120 to my friend and took his, for everyone wanting to know the temps of the previous one, temps didnt change... it HAD arctic silver 5... now it has generic white goo that prob gets like 5-7 degs hotter then as5

dsc002877wk.jpg

this picture was taken from the opposite side of my room... pointing the heat sink at my face i can see the pores, i would show how mirror it is but its hard to get the camera to focus at a angle

old thread is here http://www.hardforum.com/showthread.php?t=910235
 
since im going to have a water cooling setup all set to go before i get my new motherboard and cpu.. how much you guys think i could expect to get for this heat sink, never used since lapping
 
posted it kind of late at night last night so ill bump it to the top so more people will see
 
I just picked up some various wet/dry grits of sandpaper so I can do the same to my XP-120 tonight. Any advice? I've never lapped before so it should be interesting...Right now, I have 9" by 11" sheets of:

Ultra Fine ( 600 grit)
Super Fine ( 400 grit)
Extra Fine ( 320 grit)
Very Fine ( 220 grit)

Plan to work my way up from 220 grit with some water on there as well. My loads are shitty since I re-seated my XP-120, and it's been a good 4 days to allow burn in...and I had too much (AS5) on before, so I used less this time...hopefully a lapping will teach it a lesson. :D
 
do this next to the sink .. using water .. start with 600 and move your way up to 1500 or 2000 if you can get your hands on some.

You don't need to lap using a flat surface. I do mine with my hands and under the sink with water constantly flowing ...

Constantly rub forward and sideways with each grit until you reach your highest grit.

Once you get to that grit you will notice that you're gettin a good reflection. Grab a metal polisher, silver cleaner or whatever you have and put some on the surface and rub with highest grit and a drop of water.

Rub in a cicular motion and wash off while rubbing ... continue to rub and you'll enjoy a mirror finish.
 
Well, this guy did it with 600 grit....do you REALLY need 1000+ grit? I'll have to drive 25 minutes to go get it, if they even have it (lowe's), then 25 minutes back.
 
do you really need a mirror finish with wax when its gonna be on a CPU anyway lol, it seems like the wax would be just another barrier for the CPU to get through.
 
I usually put some kind of finish on the bottom because copper corrodes quite easily and corrosion will hinder temperature transfer more than some kind of polish. That is what I always thought anyway. I'll wait 30 seconds until someone tells me I'm wrong. LOL :eek:
 
mohammedtaha said:
do this next to the sink .. using water .. start with 600 and move your way up to 1500 or 2000 if you can get your hands on some.

You don't need to lap using a flat surface. I do mine with my hands and under the sink with water constantly flowing ...

Constantly rub forward and sideways with each grit until you reach your highest grit.

Once you get to that grit you will notice that you're gettin a good reflection. Grab a metal polisher, silver cleaner or whatever you have and put some on the surface and rub with highest grit and a drop of water.

Rub in a cicular motion and wash off while rubbing ... continue to rub and you'll enjoy a mirror finish.
Click to expand...

no YOU SHOULD use a flat surface. The biggest adv. of lapping is making the base flat, not getting a mirror finish :rolleyes: A way to insure you have a flat base is to color the bottom of the heatsink with a perm. marker, then sand, cover again then sand. I usually start with 400 grit and go all the way up to 1500 (imo, anything over 1000 is just to get mirror look). I usually lap with a piece of glass as well.
 
if you're going for looks, it probably works better, but sabre is right.. the real problem with the base of some xp-120's (the some a64 ihs's too) is that it's warped, thus the reason to use a flat surface and make sure everything is mating properly :D
 
mohammedtaha said:
i find using a flat surface hard and annoying. I do it my way and it works perfectly well.
Click to expand...

I gaurantee you that it wont work as well as using a flat surface. The point of lapping is not getting a mirror finish but making the base of the HS flat insuring good contact. if you notice, your hand is not flat therefore you wont give the hs a flat surface but you will give it a mirror finish
 
Trust me, it's flat. Not extremely flat but flat enough to have the whole core stamped on my copper base when I take it out. If I lay it on a wet flat surface it sticks to it well.
 
mohammedtaha said:
Trust me, it's flat. Not extremely flat but flat enough to have the whole core stamped on my copper base when I take it out. If I lay it on a wet flat surface it sticks to it well.
Click to expand...

The whole point of lapping is to get the heatsink as flat as possible for improved heat transfer. Sure, it might "look" flat enough, especially with a nice mirror finish, but chances are that it is not; the eyes cannot distinguish between small curves on 10^ -3 scale. I guarantee you that if you lap with a flat surface, your temperatures will improve.

What good is a mirror finish if the surface is not flat?
 
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