Lapping the IHS of my CPU: Step by Step

Eastcoasthandle

[H]ard|Gawd
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Jan 27, 2006
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Here is what I did to lap my IHS:

Step 1 Remove the Nickel layer and even out your surface area

Original CPU


Wet Lapped


I used 120 grit sandpaper (wet sand)

I started off with 120 grit sandpaper. Why? It allowed me to remove more IHS material in a shorter period of time. However, do to it's coarse nature I dipped the entire sandpaper in water (used the shower) and wiped off any access water. As the sandpaper became more dirty with IHS material I washed it again (I repeated this process throughout each grit of sandpaper). Just think of the 120 grit as a means to remove the tin layer and flatten your IHS true. Don't worry about shine or smoothness as the end results will leave a stretchy surface. I turn the IHS 90 degrees after 40 or so strokes on the sandpaper (take not I use a glass surface). Once I finished take note of how the surface of the IHS/HS looks and make a mental note and try to remove any imperfections. Clean the surface of loose debris from the IHS/HS and sandpaper. Side note: some believe that the more material you remove the better the heat drop. IMO, this depends on the situation, HS/WB used, pressured used, ambient temps, etc


Step 2 Continue to even out your surface and remove marks from 120 grit.

400 grit
Again, I wet the entire 400 grit sandpaper. I use 400 grit to remove the markings from the 120 grit sandpaper. I want to keep the IHS true and even. I turn the IHS/HS 90 degrees (as needed) and smooth out the scratches made by the 120 grit. I didn't worry about a shine or a smooth surface, I concentrate on true (flat), even surface on the IHSt. This may take some time but, when I achieved a 400 grit scratches on the IHS (maintain a true, even surface) I proceeded to go to 800 grit. Take note of the 400 grit marks left behind and try to remove any imperfections. Clean the surface of the IHS of loose debris and clean the sandpaper with water and let dry.

Step 3 smooth out your surface area

800 grit
I wet the 600 and 800 grit sandpaper and started work on removing the 400 grit markings of the IHS turning the IHS/HS 90 degrees and use the 600 grit on up to 800 grit for a flat, smooth surface. You will concentrate on keeping the surface of the IHS flat and smooth. Again, as you remove material you want to replace the 400 grit marks with 600 grit marks then 800 grit marks. Once you are finish with the 800 grit take note of how the surface looks. Take note of the 800 grit marks left behind and try to remove any imperfections. Clean the surface of IHS of loose debris, then clean the sandpaper and let dry.

Step 4 Tiddy up your lapping

1000 grit


2000 grit

I wet the 1000 grit to 2000 grit (if you have it) sandpaper and concentrated on removing the scratches from the 800 grit and 1000 grit markings on the IHS, turning the IHS as needed. I didn't need to worry about removal of material at this point. However, I did want to make sure the IHS remained true. The surface area should be true by now and I want to keep it that way. All I want to do now is tiddy up my lapping from 120 grit to 600 grit by smoothing out the IHS surface area using 800 grit to 2000 grit as much as possible at this point. At 2000 grit you are looking for perfection, no stray marks or other imperfections in the IHS.



A little blurry but here is the final product.


Side note:
It's been my experience that you get the best results when you wet sand.
It's also been my experience that using the crisscross method is a bit better

Disclaimer:
Results will vary. I am not suggesting anyone who has little to no experience in lHS lapping to attempt what I did.
 
2 questions:

1. do you have any preventive measure in place to protect the pins?

2. do you think this task can be done with machine? I am thinking about mounting th CPU on a power drill :cool:
 
2 questions:

1. do you have any preventive measure in place to protect the pins?

2. do you think this task can be done with machine? I am thinking about mounting th CPU on a power drill :cool:

1. I used that plastic back cover that came with the CPU. However, after lapping I used alcohol and compressed air to remove all the loose material from the back of the CPU. Then I let it dry. Because I have a C2D I do not have pins any more. Which made lapping easier. It's a bit more difficult to lap an IHS with a CPU that has pins . You have to aware of your finger placement on the edge of the CPU to make sure you don't touch the pins with each stroke on the sandpaper. Checking as you lap.
2. No, do not use any power tools. All you will do is warp the surface to a shine and get crappy results when it comes to heat transfer.

Results will vary. I am not suggesting anyone who has little to no experience in lHS lapping to attempt what I did.
 
2 questions:

1. do you have any preventive measure in place to protect the pins?

2. do you think this task can be done with machine? I am thinking about mounting th CPU on a power drill :cool:

No pins on a conroe :D

But, placing it in the foam pad (for those with pins) is good protection.
 
Remember, you can get a nice lapping kit from www.easypckits.com :)

I've been buying from this guy for a long time and always get great results!
 
and, do you guys think using some kind of metal polish (e.g. Brasso) will further enhance the result?
 
and, do you guys think using some kind of metal polish (e.g. Brasso) will further enhance the result?

Brasso polishes the surface, but it won't help temperatures at all. It also might hurt them.

Brasso polishing is best if used in conjunction with a small grain TIM (like ceramique), but it leaves behind a protective coating to thwart future oxidization... Make sure you clean it WELL off. Scrub with 99% alcohol.
 
Brasso polishes the surface, but it won't help temperatures at all. It also might hurt them.


yes, what I mean is to use Brasso after lapping with 2000, I think it will finish the surface even better.

Of course, the oily layer left behind by Brasoo must be cleaned :)
 
and, do you guys think using some kind of metal polish (e.g. Brasso) will further enhance the result?
No, it will not. Brasso contains a low level of abrasives that put a shine on the surface by removing fine scratches and imperfections (such as oxidation, not sure) but it takes a lot of "elbo grease". The secret to using Brasso is applying but most importantly removing it. That's were the elbo grease comes into play. If you rub Brasso on your surface for a few minutes now you need a clean cloth to remove it. You rub off Brasso on the cloth until that portion of the cloth is black. Then you remove Brasso on a new section of cloth, continue doing this until the cloth shows no reside of black material. Then you start all over by re-applying Brasso, work the Brasso on the surface a few minutes. Then you start the process of removing it on a clean cloth, section by section. In order to get a shine it will take you at least 4 applications of applying Brasso and the brutal process of removing it which takes a much longer time.

Now I, am explaining this only to be used on applicable applications not IHS use. The reason why some believe that Brasso leaves a thin layer is because (in some cases) it was not properly removed. Only wiping it off once or twice when on average it takes about 8 or 10 attempts (if the surface is manageable and flat) to remove all the Brasso off the surface. Also, once you finish use Alcohol to remove any oily residue. Not a guarantee that it will remove all the residue.

yes, what I mean is to use Brasso after lapping with 2000, I think it will finish the surface even better.

Of course, the oily layer left behind by Brasoo must be cleaned :)

the outer layer is actually nickel :D

Noted :D
 
30 minutes to 45 minutes total. The 120 grit sandpaper made short work of finding any lumps or dips in the IHS (which were none).

That doesn't seem too bad. Granted, if i were to do this, i would probably skip the 1000 and 2000 grit sandpaper so it would shave (no pun intended) some more time off the process.

How many strokes, roughly, on each type of sandpaper, or does it vary depending on the grit? I'm guessing you shouldn't spend too long with 120 grit paper, because too much of the IHS material will be worn off.
 
I wouldn't EVER use anything lower than 220grit... It just makes for more work later.

220, 400, 600, 800 is what I use on my HSFs and waterblocks.
 
That doesn't seem too bad. Granted, if i were to do this, i would probably skip the 1000 and 2000 grit sandpaper so it would shave (no pun intended) some more time off the process.

How many strokes, roughly, on each type of sandpaper, or does it vary depending on the grit? I'm guessing you shouldn't spend too long with 120 grit paper, because too much of the IHS material will be worn off.
50 Strokes before turning 90 degrees. I turned 90 degrees about 3-4 times for each grit of sandpaper (I also keep the sandpaper wet and used the shower to remove material which keep the sandpaper looking new).

I wouldn't EVER use anything lower than 220grit... It just makes for more work later.

220, 400, 600, 800 is what I use on my HSFs and waterblocks.

Agreed, it just made sense to me to use 120 grit. That alone shaved off 25 minutes trying to remove the nickel and look for imperfections only took 5mins to 8 minuites.
 
Im lazy so I use 320grit to even out the IHS then 600grit to finish it off.... didnt time it but im guessing it didnt take more than 20 min to do mine.....

50 Strokes before turning 90 degrees. I turned 90 degrees about 3-4 times for each grit of sandpaper (I also keep the sandpaper wet and used the shower to remove material which keep the sandpaper looking new).

I do the same 90deg turn but I do it every 5-6 strokes....
 
50 Strokes before turning 90 degrees. I turned 90 degrees about 3-4 times for each grit of sandpaper (I also keep the sandpaper wet and used the shower to remove material which keep the sandpaper looking new).

Righto, that sounds good. I'm weary i'll make the IHS sloped if i take a stab at lapping by not holding it completely flat; although, i suppose using glass counters this. Eh, i'll see, when i get my C2D, whether it's concave or convex because i don't want to fix something (and probably destroy it in the process) if it ain't broke!

Anyway, now i have an idea of the duration and technique, i'll be prepared if i do get a warped IHS. Thanks a lot, man.
 
Righto, that sounds good. I'm weary i'll make the IHS sloped if i take a stab at lapping by not holding it completely flat; although, i suppose using glass counters this. Eh, i'll see, when i get my C2D, whether it's concave or convex because i don't want to fix something (and probably destroy it in the process) if it ain't broke!

Anyway, now i have an idea of the duration and technique, i'll be prepared if i do get a warped IHS. Thanks a lot, man.

No problem
I wonder if there are others who have already lapped thier IHS have any pics?
 
why dont you do a full IHS removal?? You can get 3-5c drop. Risky but worth a try, expecially if your willing to sand it down.
Why not just remove it all together??
 
why dont you do a full IHS removal?? You can get 3-5c drop. Risky but worth a try, expecially if your willing to sand it down.
Why not just remove it all together??


Cuz the top is soldered on all conroes :p

It's the allendales you can remove the IHS from ;)
 
why dont you do a full IHS removal?? You can get 3-5c drop. Risky but worth a try, expecially if your willing to sand it down.
Why not just remove it all together??

When you are doing better then average on a hot day (25C room temps and higher) there is no need risking destroying your CPU.
 
The guys over at xtremesystems have some great stuff on lapping a Core 2 Duo IHS with pics and everything.

http://www.xtremesystems.org/forums/showthread.php?t=132287

And here is a great step by step guide.

http://www.thetechrepository.com/showthread.php?t=71

I have never lapped a CPU before because I was always worried about destroying the pins. However since the new Conroe CPUs don't have any pins I have been thinking about giving it a try. Are there any drawbacks to completely cleaning off the sandpaper on the underside of the CPU with rubbing alcohol or anything that you have to be careful of?
 
Are there any drawbacks to completely cleaning off the sandpaper on the underside of the CPU with rubbing alcohol or anything that you have to be careful of?

I can't remember where i heard this, or if it's true, but i though that when you expose the copper on the IHS it doesn't play nice with silver-based thermal pastes; is this true?
 
I can't remember where i heard this, or if it's true, but i though that when you expose the copper on the IHS it doesn't play nice with silver-based thermal pastes; is this true?

I'm pretty sure this is incorrect...

Rory. It has been done on extremesystems. The cpus are naked my gosh.. haha

Its capable and you get 3-5c drop .. RISKY risky.

Oh, I know it's been done. The indium solder melts at 77c... so if you've got a good soldering iron (adjustable temperatures) you could set it to 80c and get it off that way... And you'd be one of the 4 or so people that didn't destroy their conroes ;)
 
I actually polished my IHS after 2500grit and it came out like a mirror... I saw 6c drop under load with water cooling.
 
Don't tell me that.

I'm literally |__________| close to voiding my warranty :D

hehe, well to tell you the truth, I regret it myself, I had a L640 batch - the first of the new line of E6600's which did not overclock well... I lapped the IHS to get better cooling and try for a higher speed... I did get better cooling but I couldn't get it stable anywhere... and I nuclear bombed my warranty with the lapping... but I also believe it was my motherboard causing the problems (I was idling at 0c w/ tec water), so just keep an eye on my posts in the next few weeks and see what I finally get my boatanchor processor to... it probably would have been a better idea to just return the L640 and try for a 632 batch which would run at 1/3 the voltage... but since I had the cooling ability, I might be able to squeeze out similar results with the DFI 965.


even with these temps I couldn't get 3.2GHz stable :rolleyes:
http://jadefalcon.shackspace.com/Pics/Computer/coldcomputer.jpg
Gigabyte DS3 :rolleyes:
 
hehe, well to tell you the truth, I regret it myself, I had a L640 batch - the first of the new line of E6600's which did not overclock well... I lapped the IHS to get better cooling and try for a higher speed... I did get better cooling but I couldn't get it stable anywhere... and I nuclear bombed my warranty with the lapping... but I also believe it was my motherboard causing the problems (I was idling at 0c w/ tec water), so just keep an eye on my posts in the next few weeks and see what I finally get my boatanchor processor to... it probably would have been a better idea to just return the L640 and try for a 632 batch which would run at 1/3 the voltage... but since I had the cooling ability, I might be able to squeeze out similar results with the DFI 965.


even with these temps I couldn't get 3.2GHz stable :rolleyes:
http://jadefalcon.shackspace.com/Pics/Computer/coldcomputer.jpg
Gigabyte DS3 :rolleyes:

What temps did you get anyway?
 
I think I'm going to give a shot in a week after my finals are done.

It doesn't seem too hard.

I don't think my chip is concave or convex, the thing is just crooked - one side is higher than the other. I recently put a tiny amount of AS5, and the result was the right side of the chip ended up getting like 75% of the thermal paste - no wonder when I ran TAT one of my cores ran 5-7C higher on load.

What is the razor blade/CC trick? Are you supposed to place it up top and then try to shine a light under it? Or will sanding it down pretty much guarantee its flat when you hit all cooper?
 
Initially I did lap the core down to 600 grit level and wound up with virtually no drop, maybe like 3C, after removing it, didnt seem to do anything either, thought maybe my waterblock was just junk. But after increasing the core pressure, overall temp drop was down 15C:eek: 61C down to 46C

:D

before and after lapping
http://snipershide.us/images/sniper/new_puter_oct_2006/ihs_removed/before_and_after.jpg

after removing IHS
http://snipershide.us/images/sniper/new_puter_oct_2006/uggh/increased_core_tension_2.jpg
 
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