Adventures in lapping - Overclock.net

leimrod · 12-03-06

Ok, so since reading about the ins and outs of lapping a few weeks ago, I decided with my next cooler upgrade i'd give it a go. I've been through a few iterations since and think I have the best method for doing it down.

First off here is my first attempt, I didn't want to chance messing up my new Tuniq, so I practiced on a spare stock AMD HS.

First off you will need a flat surface (i.e. marble or glass) I had a few spare photo frames around so I decided to use those, and some wetordry sandpaper, in the picture below I have a selection of grits that can usually be bought at any local motor factors (i.e. grits 220, 400, 600, 1200, 1500), any higher than this and I found I had to order abroad.

Next get your motherboard and HS

remove it

Do the penny test for composure

Now, i've since reworked this setup, but i'll get to that later. But for this I duct taped the piece of sandpaper to the glass in the frame before starting

I then proceeded to go up to the grits moving the heatsink up and down on the sandpaper, rotating it by 90' every 2-3minutes. This particular HS was VERY convex, I wish i'd taken a photo, but it took a good 20 minutes of lapping to get rid of the bump in the middle of it. The picture below is the result of this method of sanding up to a grit of 1500... not that good I know

But at least its flat)

Next I ordered some lapping kits from Dave at easyPCkits.com, for the AMD HS I used the heat sink lapping kit as i'd already gone up to 1500, I only used the grits 2000 and 2500 that where included. I also reworked the setup by removing the glass from the frame and duct taping the sandpaper directly to it. I also found that putting a few drops of water on the glass helps the sandpaper stick in place.

Here are the results

Better but not great, the one thing I found is that on the easypckits guide it tells you to wet the paper thoroughly before using, when I did this I found the grit would clump up on the sandpaper and leave deep scratchs in the heatsink, that would require going back to a lower grit to remove. So imo, its better to leave the sandpaper dry whilst sanding as the metal dust can easily be wiped/blown away if it is dry. Also I started sanding the heatsink by rotating it in a counterclockwise manner on the higher grits which I found to be effective.

Next i'm going to show you the next method I used for sanding the Tuniq Tower 120 with better results. Then i'm going to be lapping my Opty 165 which i'll log also.

Any opinions ideas welcome.

leimrod · 12-03-06

Here is my second attempt, a little wiser, lapping the excellent TT120, to better results.

Lapping a Tuniq Tower:

Anybody who knows anything will know that atm (I use that term liberally

) the Tuniq Tower 120 is the best non TEC aircooler out there. But compared to the likes of your Scythes and Zalmans the finish on the base is horrible. Almost as bad as a stock AMD HS. In fact I found the copper on the sides and top of the copper plate to be shinier than the bottom

Heres the euro test (not good

)

First I removed the fan unit, which, to my surprise is not held in by anything, you just push the fan up through the HS to remove it.

This is the setup, I used: Glass, duct tape, premium lapping kit, Articlean, some Qtips and lint free cloth (lens cleaner)

The method I used for lapping this time I had perfected on the previous AMD HS. I do 2 minutes going up and down, then I wipe off any metal dust from the paper with a lint free cloth, then rotate the HS by 90 degrees and repeat for a 360 degre rotation, I then do a number of minutes moving the HS in circles, checking the surface and corners to make sure everywhere is being lapped evenly.

The way I held the heatsink is in the pictures below. I found the weight alone of the heatsink was sufficient for sanding so I applied no extra pressure down on it. I also found applying pressure would cause the edges to snag the paper, you can solve this also by beveling the edges by stroking along them a few times on the sandpaper.

here are the results, I used the premium kit off easypckits which included girts of (400, 600, 800, 1000, 40 micron, 25, micron, 20 micron, 15 micron, 10 micron) This kit IS a lot superior to the original sandpaper I was using and I found I started to get a good mirror finish after using only the 400 grit paper.

This is at 600 Grit

1000 Grit

10 Microns

I'm very happy with this finish, I'll be lapping my Opty today so I should have the pics up by this evening. Theres something sexy about having bare copper on copper between the HS and CPU

, although there'll be some coollabs liquid pro to buffer them

Niko-Time · 12-03-06

Thats a very nice job, well done

frostbite · 12-03-06

Some nice work there

**The Duke** · 12-03-06

Very well done

blackeagle · 12-03-06

good job, I just lapped my tuniq too, Im going to post a thread today to show how I went about it. Nice job though!

alk · 12-03-06

Nice. If you fancy an even shinier finish, get some metal polish on there, like brasso.

leimrod · 12-03-06

what does brasso do exactly? Is it an abrasive, or just an oily polish?

I've got some of that "finishing paste" from easypckits. I'm going to hook up my dremel with a felt bit and see if I can get a better shine off it

All this effort to have it out of site

that extra 5 or 6 degree drop better be worth it, i'm hoping to get my crappy opty stepping to 3Ghz

waqasr · 12-03-06

thats a good lap job..looks very nice..but bear this in mind..your are NOT after a shiny finish..it is SMOOTH and FLAT finish that you want..obviously after sanding so much it will be shiny but shiny is not the objective..also i was wondering...ive lapped my ihs and BT...and used very VERY little bit of AS5..would it have been better to have used nothing at all..as both the surfaces are super flat??

leimrod · 12-03-06

its not possible, at least by conventional means, to get both of the surfaces COMPLETELY flat, there will always be scratchs, holes, pits on the surface that aren't visable to the naked eye. Although the shinier the surfaces the less TIM you'll need.

Why not try it without TIM and monitor the temps as soon as you boot into BIOS? Another option i've heard is to rub in the TIM on the surface of the HS and IHS then wipe it off with a lint free cloth. This will leave a residue of the TIM in the holes and scratchs, but will also allow for the majority of the metal surface to be directly touching. I don't think i'll be trying either as i'm using liquid pro, which afair needs to be spread out over the entire IHS

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Adventures in lapping

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