Need Primer on Lapping Heatsinks

[Spacemobile1]

OK, I know the why's and the expected results of Lapping. But I don't know the HOW part. Can someone explain the lapping process to me. How do you guarantee flatness, what types and grits of paper is used, or do you use a lapping compound. Any help from all the experts here would be greatly appreciated.

Thanks:nervous:

[cloasters]

Welcome to AOA Forums, Spacemobile1! An excellent guide to CPU lapping is available at http://www.overclockers.com.au/techs...d1/index.shtml .

It's dated, as the majority of CPU's don't come in a nickle-plated copper jacket any more. Nonetheless, it's an excellent guide to lapping heatsinks. Very little extrapolation is needed. Most folks don't recommend lapping modern glass CPU's, btw.

[kat]

its not to big a deal , go down to you local hardware and buy a piece of glass 12"x12", 4 sheets of 400 grit ,4 sheets of 800 grit and 4 sheets of 1000 grit paper, duct tape the glass to your work bench , and then duct tape the paper to the glass, press lightly and work in a circular motion , being carfull not to tip the hs, when you get a uniform apperance its time to go the the next higher grit

piece of cake good luck


oh ya the cost of this little project was about 6 bucks

[Spacemobile1]

Much thanks to Cloasters and Kat,

This gives me the info I needed. Now I feel confident on my next project.

I have checked out many forums, and belong to a few, but this one seems to have the greatest expertise on hand.

Once again, Thanks,

Dana

[dimmreaper]

Originally posted by kat
a piece of glass 12"x12"

You'd be suprised how uneven the surface of glass is. Smooth it is, but it's just not as flat as you'd think. I surface ground(within 0.0005"!) a piece of 1/2" thick tool steel for my lapping pleasures, it works quite good.

But I'm a perfectionist, glass should work fine for everyone else.

[Holst]

Originally posted by dimmreaper
You'd be suprised how uneven the surface of glass is. Smooth it is, but it's just not as flat as you'd think. I surface ground(within 0.0005"!) a piece of 1/2" thick tool steel for my lapping pleasures, it works quite good.

But I'm a perfectionist, glass should work fine for everyone else.

I just use the kitchen worktop. Its plenty flat enough for heatsinks.

I only go down to 800 grit paper as well. Some people go all the way to 2000 and get a mirrir finish..but I dont think you will see any better cooling so why bother ?

[kat]

Originally posted by dimmreaper
I surface ground(within 0.0005"!) a piece of 1/2" thick tool steel for my lapping pleasures, it works quite good.

say how much is that going to add to the cost of the project:-D :-D

when i lapped my hedgehog i went to 1000 grit ran it for a couple of weeks and then decided to go to 1500 and then polishing compund...made no difference it sure looked nice shame you cant see it

[Cyberey66]

Originally posted by kat
decided to go to 1500 and then polishing compund

Polishing compounds are a no no. They look nice but actually take away from heat transfer. Don't get sucked into looks, just go for even flatness. (Who sees the bottom of you heatsink anyway?)

BTW, i found it much better to apply almost no pressure on the heatsink. If I applied pressure I got a noticable crowning effect. Periodically check the botton of the heatsink for crowning.

[dimmreaper]

Originally posted by kat


say how much is that going to add to the cost of the project:-D :-D

Honestly Kat, I couldn't let you have it for less than $150, tool steel plate is expensive, tempering is expensive, and it took a lot of work to get it that damn flat. And just think, it's only 8" square! Unfortunetly if the room temperature raises or lowers 10F it becomes noticebly less flat via laser, so you have to use it at 74F dead nuts for best results. But like I said, I'm a perfectionist . . .

I wet sand with 1200 paper myself . . .

No polish though, that just clogs up the pores in the metal that should get filled with arctic silver . . .

[dimmreaper]

Originally posted by Holst
Some people go all the way to 2000 and get a mirrir finish..but I dont think you will see any better cooling so why bother ?

If you didn't see the advantage with a flatter smoother heatsink base, it may be that you aren't getting the paste optimally thin. You just need to barely paint the arctic silver on the core, when you can see through it it's too thin. You also want to smudge a bit on the heatsink and then rub it in and wipe it off with a piece of "cling-wrap" plastic(don't use cloth).

Again, you're all seeing the perfectionist in me.

[Random Nonsense]

Originally posted by dimmreaper
You'd be suprised how uneven the surface of glass is. Smooth it is, but it's just not as flat as you'd think. I surface ground(within 0.0005"!) a piece of 1/2" thick tool steel for my lapping pleasures, it works quite good.

But I'm a perfectionist, glass should work fine for everyone else.

im lucky, at college we have flat tables, they are as close to perfectly flat as is possible! some moron attacked one with a hammer, so i used the undamaged portion to lap my sink. thing is, i dont think glas will be too uneven, we are all using sandpaper after all, which as far an i know isnt a uniform thickness all the way through!

ideally i guess we should lap the sink TO the core, but then u are getting into dangerous territory.... i dont think an AMD core would take it, but you could lap the heat spreader on an intel chip to a heatsink safely using some valve lapping compound. jeff since you have access to that kind of thing maybe you could give it a try?

[dimmreaper]

Originally posted by Random Nonsense
but you could lap the heat spreader on an intel chip to a heatsink safely using some valve lapping compound. jeff since you have access to that kind of thing maybe you could give it a try?

1) I have access to valve polish, but I don't ever use it, I ditch imperfect parts in favor for new ones.

2) I don't have an Intel CPU with the IHS.

3) The polish would probably clog pores and crevasses not allowing them to be filled with heatsink paste.

4) If I did have an Intel CPU with the IHS, I wouldn't care for the down time. CPU hours are just too valuable to the hardcore 24/7 folding@home nut case like me.

[Spacemobile1]

Just wanted to check back and let you guys know that it worked out great. I lapped my Glaciator II HSF up to 1500 grit wet. Installed this baby on my XP1700+ and removed the Vantec CCK-6027D that was previously resident on the CPU. The Vantec was NOT lapped. Anyway my CPU temps have dropped by a full 10 degrees C. I am very impressed with both the Glaciator and with the lapping job. Thanks again for everyones help and advice.

[kat]

sweet...


like jeff said

"for my lapping pleasure"

[Holst]

Originally posted by dimmreaper
If you didn't see the advantage with a flatter smoother heatsink base, it may be that you aren't getting the paste optimally thin. You just need to barely paint the arctic silver on the core, when you can see through it it's too thin. You also want to smudge a bit on the heatsink and then rub it in and wipe it off with a piece of "cling-wrap" plastic(don't use cloth).

Again, you're all seeing the perfectionist in me.

My point was that its flat after using the 800 grit.

I have laped upto 2000 and saw absolutely no advantage temperature wise.
It looks nice but thats not the point.

I get great temperatures.
There arnt many people who run 40*c with a £14 heatsink full load.

[Cyberey66]

I guess I'm the getto OCer. The highest grit sandpaper that the stores sell around me is 600, so I'm stuck with that. As for the glass, I just took a picture frame off my wall and used that. I soaked the paper in water and stuck it to the glass and started lapping. 600 actually doesn't do bad at all, it's alot better than non-lapped on most heatsinks. I followed up with some arctic alumina, first cleaned the heatink with Goof Off, took a sandwich bag and rubbed some alumina paste in, applied a thin layer to the CPU core, and put it back on.

My new temps were about 27° idle, 30-32° normal use, and 40-43° load for a few hours. The load temps were really high, but I think it is the fact my heatsink is pretty small. The heatsink is the OCZ glacier2.

[Spacemobile1]

Originally posted by Cyberey66
I guess I'm the getto OCer. The highest grit sandpaper that the stores sell around me is 600, so I'm stuck with that.

Most hardware stores don't carry the extra fine grits. You need to go to an auto parts place, like a Pep Boys or the like that carry automotive finishing supplies. They will have up to 2000 grit on hand.

[robbie]

Originally posted by kat
its not to big a deal , go down to you local hardware and buy a piece of glass 12"x12", 4 sheets of 400 grit ,4 sheets of 800 grit and 4 sheets of 1000 grit paper, duct tape the glass to your work bench , and then duct tape the paper to the glass, press lightly and work in a circular motion , being carfull not to tip the hs, when you get a uniform apperance its time to go the the next higher grit

piece of cake good luck


oh ya the cost of this little project was about 6 bucks

OR if you got a stereo cabinet take the glass off of it and use that.

Save ya a few bux.

Rob

[Nate-X]

Thanks for the info guys.. Was thinking about lapping my ax-7bs once I repace my mobo.. I have to clean my processor as well... damn thing's a mess.. hehe