Heatsink Lapping

[MagicBox]

Well.. to give this topic its own thread AND given the fact that I'm in the middle of lapping my new Volcano 7+, I decided to post about my experiences. I actually should make pictures of the process :smokin:

There are several guides on how to lap and what equipment you'd need. I went with 400, 800, 1000 and 1200 grit sandpaper. So for now, I'm still in the first phase, using the 400 grid. I'm using mirror glass tiles as lapping surface.

So what's the first thing I noticed when I did the first lappingrounds on my Volcano 7+? It is NOT FLAT at ALL !!. Sure the base had long grooves visible to the eye, but it was impossible to see it was not flat untill I made some progression on the lapping. So my first impression... if you haven't lapped your Volcano 7+, do so!

I will add a picture of the base as soon as my digicam's battery is recharged :blah:

-Magic

[MagicBox]

Here we go, first picture. Notice the more glimmering circle. The inner area and the edges haven't been sanded yet, so it's clear to see that the heatsink's base was slightly hollow.

-Magic

[Chezman29]

Thanks for the pics Magicbox.

I have posted numerous times to the necessity of lapping the HSF whether your temps are high or not.

I ALWAYS lap my HSF. Then I don't have a doubt in my mind that the base is FLAT, my thermal paste is applied correctly and if my temps are still high, I don't have to take a look at the HSF.
I can go straight to looking at other variables.

I ALSO check for flatness after a couple months or so, or whenever I have to pull the HSF after a while to double check it.
Metal expands and contracts under heat and cooling. During this process, it can also warp. Ever so slightly, more in other configurations, especially "Slugged" HSF.
So I do a quick cleanup of the old thermal paste, block sand to check for flatness, and reapply my favorite thermal paste - Cooler Master by Shin Etsu, its as thick as peanut butter but cuts down temps by about 4c off of ASIII. So I like it. It is a little hard to get used to the consistency, although it works great.

Great pics,
Chez

I like to think of it as "changing the oil, or preventative maintainance". :cheers:

[MagicBox]

I like to think of it as "changing the oil, or preventative maintainance".

Yeah, that pretty much comes close :) I finally have all the parts I needed for the new rig I am trying to put together, and I have this mindset of wanting to do everything right the first time. I'm glad about finding something about lapping, otherwise I simply would have put the HSF right on the CPU with some grease. But this time I'm paying attention to every little detail that could increase performance.

Anyways, after scrubbing that HSF over the 400 paper, I'm almost done. It's an intensive job to do too! Don't they say patience is a virtue...? lol.

-Magic

This is what it looks like now:

[Chezman29]

You are going to use something like 1000, or 1200 for the final sanding right?
I use wet/dry 1000/1200 for my final sanding.
To be honest, I have never had to use anything close to 400!!! That is some gritty stuff. That thing must have been off pretty bad!
You want to get it as glassy as you can, yet have enough "ridges" to "hold" the thermal grease. Kind of an oxymoron.

When I use the CM by Shin Etsu, since it is so "pasty" I add a thin coat via a Credit Card, then set the HSF in place, then remove it, check the contact patch and see how it looks, thickness wise and all, then I clean both surfaces again and reapply in the right location and adjust the amount of paste if necessary.

I think Smokin' PC might be right behind you in trying this out to lower his temps...

Have fun,
Chez

[Chezman29]

try this guide for lapping: http://overclockersclub.com/guides/...ppingguide.php#


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Minibubba posted this in another thread, and I thought it might be useful to compare your pics to it.
It looks like they went all the way up to 2000 grit wet/dry. I think wet/dry is key as well.
Personally I only use up to 1200.
Regards,
Chez

[MagicBox]

And here we got the (I thought at that time) final finish with 800. the flash garbles up the picture a bit, but you can still get the idea:

EDIT: This was with 400, not 800.

[MagicBox]

then I went on with the 800 grit paper, however.. I noticed the middle was still very very very little hollow. The 800 texture showed a little 400 texture dot in the middle. So I cut me a new workable piece of 400 and gave it another few rounds. After this, I continued again with the 800 grit and finished with both left-to-right, up and down and circular movements. The result is this:

[MagicBox]

And here with 1000. I think around up to 1500 would be more than enough. Don't gotta make the valeys etc. smaller than the thermal grease particles. But so far, everything looks good. Since I'm done with the 1000 grit sandpaper, I'm gonna wash the heatsink, dry it with a dryer and sand the base dry with the 1200. So, hopefully tonight I'll be able to put the mobo, CPU and heatsink together :)

[MagicBox]

Well! I'm finally done. Afer thoroughly cleaning the heatsink (and carefully the base) I gave it the last sanding spin, all dry on the 1200 (to get rid of any lapping / cleaning remnants) and it's all ready to be prepared with thermal paste. But for now, the finished lapping result (at 1200 it's getting pretty mirrorish):

[Chezman29]

That looks a heck of a lot BETTER now than it did.

Just a little FYI. If you wet sand it with dishsoap for your final sanding you will actually get a better finished product.
Dry sanding is actually a lot harsher and leaves a lot more scratches and stuff behind.
I don't know how much of a difference as I have never just dry sanding it. I do know that it shines up sweet though. I never tried it until I read it in a lapping guide and they suggested using some dishsoap, so I tried it, and it worked.
Just in case you wanna try. By now I am sure you have had enough.

Looks good though. I am sure lapping it won't HURT your temps!!!

Chez :cheers:

BTW I bet if you go back and put a little thermal paste on your HSF, than mount it, take it back off, and then look where your CPU touches your HSF. IT will be in the CENTER of the original concave that you had to sand out. THAT is the product of the heating and cooling of the metal. The center being the hottest adn the outside cooling down before the center does.
THAT is why I double check mine after a couple months.
I haven't noticed it with Aluminum blocks as bad. Copper is a softer metal and has a tendency to warp easier.
Yours looks like it might have been on quite a while, just a guess.

[MagicBox]

Yeah I would think so and eventually redid it with water and dishsoap. The guide you provided me is where I got my general information from. From a different site how to make a useful lapping plate. It was fun doing that research. Here's a pic of the heatsink base prepared with thermal paste. It's a dull blob in the middle, exactly what it's supposed to be like. Too bad, I liked the shine hehe. Oh well. The final pic will show the seating of the heatsink on the mobo.

[E^vol]

MagicBox : NICE ! :thumb:
I've been meaning to lap my V7+, but haven't got around to it yet....:thumbs do
Let us know what your temps are when you get it up and running. :cheers:

[The Evolved One]

hmmm...
if i had a decent heat sink i may try this.... but seeing that i dont... can't be bothered... i was just curious what temp drops do you get from lapping? is it noticeably differnt?

The Evolved One

[Neil2094]

Lummy! I better do that do my 7+ seeing as its not being used at the moment. Wow what a difference! :hammer: :thumb: :thumb: