Heatsink Lapping

[HOCP4ME]

I was thinking of buying the heatsink lapping kit on FrozenCPU.com. If I understand correctly once I get it I just:

1. Use Arcticlean to remove old AS5
2. Wet sandpaper with household cleaner
3. Lap heatsink
4. Clean heatsink with ArctiClean again
5. Reattach heatsink with AS5.

Is this correct? Also, is the weight of my heatsink enough or should I still apply some pressure?


Oh, and I assume I should also lap the IHS on the CPU as well, so that both surfaces are flat, right?

 

[memnoch7]

why buy a kit when you can so easily buy better quality sanpaper in your local hardware shop? look for automotive sanpaper, it can go up to 2000grit and its like 1$ each...

Also you don't need articlean. by sanding you remove the old residual thermal paste anyways!

 

[bmwolf]

The weight of the heatsink is plenty especially if it is copper. By applying pressure with your hands you will inevitably end up with an uneven surface because your weight will shift so much. Also you could also buy the supplies at a local autozone or equivilant. and achieve the same results if not better.

here is a mini tutorial i made on another site:

http://portfolio.iu.edu/bmwolf/Before1.jpg
http://portfolio.iu.edu/bmwolf/After3.jpg

http://forums.cgsociety.org/showpost.php?p=2487555&postcount=39

Also you may wish to use denatured achohol instead of acetone as i mentioned because acetone tends to leave a little film.

 

[ozziegn]

Here's what I use when I lap a heatsink:

400, 1,000 and 1500 grit wet/dry sandpaper along with a 3/8" thick piece of plate glasss which provides me with a 100% perfectly smooth sanding surface. after all, what good will all that sanding do if you dont have a perfectly flat surface to go by?

anyway... I start off by using 400 grit. it lets me know pretty quickly as to how much of the heatsink's base is out of wack and it also lets me know approx how long its going to take me. usually all four corners on a heatsink's base will turn copper first which is the first indication that the heatsink's base isnt perfectly flat. so I just keep on sanding until the entire bas of the cooler has turned to copper cooler. that tells me that I'm pretty much well there.

after I get to an all copper color or surface, I take the 1,000 grit wet/dry sandpaper and I start smoothing out the base even more. I'll usually use about three sheets of the 1,000 grit just to make sure its pretty smooth.

last but not least is where the 1,500 grit comes to play. this stuff is pretty freakin' fine and it will just about take the copper base right down to a reflective finish. I usually will only go through two sheets of 1,500 grit for the final sanding process.

so from start to finish, lapping a heatsink like an XP-120 will usually take me about three to four hours. but in the end its worth it because the base ends up being a damn-near mirror copper finish.

 

[HOCP4ME]

Well, it looks like all the "kit" is is an assortment of sandpapers and a flat block to sand with. So, why should I buy each individual grit at Autozone when I could just order the kit and get all of the grits up to 2500, which I imagine would make a better finish than 1500?


So, I think I'll take the 400 grit and lap the heatsink until the base is an even color, then repeat that with the other grits, gradually stepping up until I get to 2500, giving a polished finish. Then, I'll use ActiClean or denatured alcohol to clean it. Does that sound right?


Also, I still want to know if I should also lap the IHS on the CPU, and will I need another kit to do that or can I reuse the same sandpaper?

 

[bmwolf]

This guy does. It wasn't worth it to me.

http://www.motherboardrepair.com/index.php?sec=hslapping

I'm sure the kit will work fine. Just know there are other alternatives out there, if your in a pinch, don't want to pay shipping, etc...

 

[memnoch7]

Well, it looks like all the "kit" is is an assortment of sandpapers and a flat block to sand with. So, why should I buy each individual grit at Autozone when I could just order the kit and get all of the grits up to 2500, which I imagine would make a better finish than 1500?

By experience, you will not get any temperature performance gain between a 1500 grit and 2500 grit. You might get a better finish, but it is all that you will get (you can't really show it off)

So, I think I'll take the 400 grit and lap the heatsink until the base is an even color, then repeat that with the other grits, gradually stepping up until I get to 2500, giving a polished finish. Then, I'll use ActiClean or denatured alcohol to clean it. Does that sound right?

You have to clean your heatsink between each time you change sanding paper to remove all solid residues.

Also, I still want to know if I should also lap the IHS on the CPU, and will I need another kit to do that or can I reuse the same sandpaper?

Sure you can lap that. it is in general very well lapped anyways, so you won't gain much. And you can reuse your kit for that.

 

[ozziegn]

screw that FrozenCPU kit which will cost you at least $12 w/ shipping. I can almost guarantee you that the included sandpaper in that kit wont be enough. and then what? you're still going to have to buy some wet/dry sandpaper locally which in turn is going to cost you even more money.

I buy my wet/dry sandpaper from a local automotive paint supply shop. he sells each wet/dry sandpaper packets for like $2.50 which includes six sheets which are something like 5" X 8" or so. you can go to a local glass shop and ask them if they have a spare piece of plate glass which they'll probably give it to you for free from their throw-away pile.

 

[HOCP4ME]

screw that FrozenCPU kit which will cost you at least $12 w/ shipping. I can almost guarantee you that the included sandpaper in that kit wont be enough. and then what? you're still going to have to buy some wet/dry sandpaper locally which in turn is going to cost you even more money.

Well, in that case I will buy the sandpaper myself.


So, I'll get 400, 1000, 1500, and 2000. (I need 2000 for something else anyway so I might as well use it on the heatsink.) Then, I'll look for a piece of plate glass to use as a lapping block. I will use denatured alcohol to remove old thermal paste and clean between each step. Then, I'll do the same thing with the CPU. Lastly, I'll put a very small amount of thermal paste on.

I just have a few questions now after reading the guide that bmwolf posted in his last post:

1. The guide said to use straight line passes for round heatsinks and random patterns for square heatsinks. I'm pretty sure my heatsink, the CNPS7700CU, is round, but can someone else verify this?

2. The guide says that cleaning the HSF with alcohol between sandpapers is not required, just a quick rinse. Then it says to heat the HSF and clean it when you're done. Is this true, or do I need to clean it between sandpapers?

3. Since you said the CPU is flat to begin with, could I start with 1000 grit instead of 400 for the CPU to save some time?

Thanks everyone for the replys, I really hope this lowers my temps enough to make it worth it. I have heard of someone who has my heatsink gettting it down to XP90-C temps by lapping it, so I hope he's right.

 

[Akuma]

The CNPS7700 has a square-ish slightly curved base...

Don't bother lapping the IHS. It's kind of dangerous and you probably won't see any temp drop.

 

[memnoch7]

yes yes, it is very important to lap round heatsinks in a straigt line patterns. Please use a ruler and lap along its line. Based on extensive study on thermo-dynamics, Straith lines patterns increase the vortex of heat transmission of sub-atomic zeta-particles for circular surfaces by inducing the ThermalShift effect through its thermal-torque....


Seriously, you make lapping a heatsink sound like such a complicated task. Just hold the heatsink steady and sand it, water-clean it, sand it again, do not apply too much pressure and use common sense.

Do not read one review on how to do things and beleive it to the letter, google around and capture and understand the general idea of lapping.

 

[fluxion]

Sure you can lap that. it is in general very well lapped anyways, so you won't gain much. And you can reuse your kit for that.

the main thing with lapping a heatspeader is getting down to the copper base, but they can be a bit uneven. mine had an almost random surface pattern, it was weird.

 

[KPAthlon64]

yes yes, it is very important to lap round heatsinks in a straigt line patterns. Please use a ruler and lap along its line. Based on extensive study on thermo-dynamics, Straith lines patterns increase the vortex of heat transmission of sub-atomic zeta-particles for circular surfaces by inducing the ThermalShift effect through its thermal-torque....


Seriously, you make lapping a heatsink sound like such a complicated task. Just hold the heatsink steady and sand it, water-clean it, sand it again, do not apply too much pressure and use common sense.

Do not read one review on how to do things and beleive it to the letter, google around and capture and understand the general idea of lapping.

seriously?!? shit, i TOTALLY didn't think that the ThermalShift effect mattered while using heatsinks with this low of a thermal-torque to them. i know with watercooling and especially vaporchill, the thermal-torque induced is just crazy, and lapping one of those babies does a GREAT deal, but one DOES have to watch out for the direction, because like memnoch7 said, you MUST watch out for the ThermalShift effect while lapping these higher end cooling devices. oh well, i better go redo my heatsink, now that i know my circular lapping will be inducing the ThermalShift effect, and possibly ruining my zeta-particles :S

thanks for the tip, memnoch7, i owe you one

 

[HOCP4ME]

yes yes, it is very important to lap round heatsinks in a straigt line patterns. Please use a ruler and lap along its line. Based on extensive study on thermo-dynamics, Straith lines patterns increase the vortex of heat transmission of sub-atomic zeta-particles for circular surfaces by inducing the ThermalShift effect through its thermal-torque....


Seriously, you make lapping a heatsink sound like such a complicated task. Just hold the heatsink steady and sand it, water-clean it, sand it again, do not apply too much pressure and use common sense.

Do not read one review on how to do things and beleive it to the letter, google around and capture and understand the general idea of lapping.

Lol, okay. I just wanted to make sure I lapped it in the best way possible, but you're right, I guess it is pretty simple. I'll just mark the base, sand it until the marking is gone, then rinse and switch to the next grit and repeat that until I'm done.

I don't know if I'll lap the CPU, depends on how much time it takes to lap the HSF. Lapping the CPU couldn't make my temps any worse, could it?


Thanks everyone for the help, sorry I made such a big deal about such a simple thing.


EDIT-I have just one more question. Someone said they "go thorugh" 3 sheets of 1000 grit sandpaper. How do I know when I've "gone through" a sheet?

 

[Justintoxicated]

Don't Bother Lapping it to more than 800 grit. Yuor wasting time and money There will not be a performance increase. In fact I have read you can actualy reduce perfomance. Your going to be using Thermal past anyways which will fill in all the tiny pits and valleys left form 800 grit. You reduce surface area when going beyond 800 grit and there will still be thermal past between the HS and CPU.

Make sure to lap on a piece of glass to ensure a level surface.

 

[fluxion]

1000+ grit is like your self-reward for spending hours polishing your pos heatsink, i wouldn't take that away from any man.

 

[Susquehannock]

>>>>>
You have to clean your heatsink between each time you change sanding paper to remove all solid residues.
>>>>

100% agreement here. Rinsing with clean water is VERY important, not just when changing
paper, but after every few passes as it removes any stray particles. Yes, it becomes all the
more important the more smooth your finish.

Don't Bother Lapping it to more than 800 grit. Yuor wasting time and money There will not be a performance increase. In fact I have read you can actualy reduce perfomance. Your going to be using Thermal past anyways which will fill in all the tiny pits and valleys left form 800 grit. You reduce surface area when going beyond 800 grit and there will still be thermal past between the HS and CPU
>>>>>

Agree with that too - anything above an 800 grit finish is a waste of time provided
it is even & consistant. Certainly not going to give a huge temp advantage, not for the extra work involved.
And trust me, I've had some pretty darn perfect surfaces on my sinks :


^^^ = 2,000 grit finish, no polishing compound at all. That just creates more work since
they leave residues behind which must be removed.

Relapping the above surface back to an even 800 grit saw no increase in temps.
Several similar experiments netted the same results so it's not just an isolated case.

 

[ryuji]

it is in general very well lapped anyways, so you won't gain much.

bullshit, lapping my ihs dropped temps 5 degs C alone and thats comparing to baked on as5

 

[memnoch7]

bullshit, lapping my ihs dropped temps 5 degs C alone and thats comparing to baked on as5

that may be true. that is why i stated "in general". Forget about lapping the IHS; the ideal (in terms of max heat dissipation) thing to do, is to remove the IHS, *carefully* lap the core and then install the heatsink (without IHS) with as5. This should drop another 4-5 C.

 

[fluxion]

i'm pretty adventurous, but that's just a tad too risky for me. maybe one of these days i'll try that, when this system is just an extra that i'm free to play around with.

 

[ryuji]

the prescott ihs's are soldered to the core, which gives them pretty damn good heat transfer efficiency there damn close to not being on there at all and your just cooling the ihs and you expect load temps to drop more when load temp vs my idle temp is literaly 5 degs C(lapping did nothing for idle)

 

[Susquehannock]

That may be true, but know that solder is notorious for being a very poor thermal conductor.

 

[ryuji]

That may be true, but know that solder is notorious for being a very poor thermal conductor.

maybe intel found somthing thats just as good but conducts heat well? i dunno what they use, but think about it, have you ever seen a bare core prescott? my friend said its impossible to remove the ihs without ripping the core out with it and hes no noob, hes one of the big guys at XS

also, the late model northwoods were soldered, nobody noticed

 

[Susquehannock]

Wouldn't surprise me a bit if AMD and Intel used a special solder under the heatspreader.
Was only saying that in general solder is pretty poor thermal conductor.

 

[KPAthlon64]

Wouldn't surprise me a bit if AMD and Intel used a special solder under the heatspreader.
Was only saying that in general solder is pretty poor thermal conductor.

dont think it can be solder at all, because people pull the IHS off a lot, just pop's right off after some prying from a razor, as far as i've heard. some ppl put it in the freezer to brittleize the glue (awesome word ) before taking it off, i haven't done it myself, i've lapped my IHS and figure that reallistically, a piece of copper that's like, 1/16-1/8 of an inch thick that is right on the core will probably not do TOO much
the biggest problem i have with the idea, is that given the top isn't perfectly flat, the bottom probably isn't either, and that'd be one hell of a problem to lap, even without it being attached to the proc, but once it's taken off, i don't think there's a good reason to put it back on, cuz its ONLY going to keep things hotter, if anything at all. my point, i guess, is that if anything the IHS is going to hinder heat transfer, but since its so thin and made of coper, it should be minimal

 

[XteriorMotive]

if you are going to lap the heatsink would you lap the processor as well to make them both smooth