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Lapping and thermal compounds

ChadwickVM

n00b
Joined
Mar 24, 2004
Messages
10
#1. I'm new. Hence the Newbie Cheeze.
#2. Search function is disabled at the moment.

That being said. What is this lapping I hear so much about (sand down your heatsink and then. . .) and where can I find information on it and kits for it? Also, what is the best thermal compound to use? I've looked at a lot of old PCM+ articles and I've shied away from that. I was also looking at AS5 and ceramique. My only concern with AS is electric conductivity, which i'm not sure is a huge issue.
Lastly if you have any heatsink recommendations, they'd be much appreciated. Right now I have a Volcano 11 - Xaser edition that is sitting around not doing much. Its rated for upto an "AMD Athlon XP 3400+" and i'm only upgrading to a 3000+ 333mhz fsb.
This will not be overclocked.
 
AS5 is basically the best stuff around right now. You will have no problems with conductivity. Spread a very thin layer on the core only.

For lapping there isn't any "kits" that I know of, basically google for lapping hs. What you do in general terms is get sandpaper depending on how rough your hs is start at like 600 and go all the way up to atleast 1000 or 2000 if you can get it.

Quick warning DO NOT sand by hand, look for some good guides, and wetsand.

The hsf you have should be fine, I don't know the model myself, but if it is rated for your cpu and you are not overclocking try it out, if it is to loud or temps are to hot then worry about getting something else.
 
Doing a lap dance is the process of rubbing an abrasive substance in a circular motion against a [H]ard surface, polishing a surface (not the nasty). And at the same time making that surface flat. I did it to my GPU as well as my heat sinks. Get a flat surface and as Shieze stated start with a 600 wet or dry paper and work your way up to a finer grit. Water helps but isn't necassary. you'll just use more paper. I used a flat table top (formica) for my CPU cooler and a flat block of wood 1/4 x 2 x 4 inches for my GPU. Clean afterwards with isopropyl alcohol 91%

I tried AS3,AS5 and cerimique all are within 2 degrees so if your really worried about shorting use the cerimique. Not alot though, if perfectly flat surfaces could be achieved no compound would be needed. Heat sink compond works on the microsopic level.

Lapping brought down my temps around 4-5c
 
Thanks a bunch. I'll start Google searching on it. There was something i read about some company creating a lapping kit; maybe at Tom's Hardware. Regardless, it seems like buying any sort of "kit" from any company would be a waste of money seeing as one could get the materials so easily.
 
I highly recomend this kit for lapping. The guy had a contest once, and sent me and some others a free lapping kit. It works great :) you can order it with glass or without.
http://www.easypckits.com/

Basically for lapping you get some wet sand paper, get it all wet and place it on a flat surface (kitchen counter, marble, glass...). There are different methods for the next part, but what I do is mark the whole surface of the HS with a black sharpie, put a little drop of kitchen soap on it and gently move it back and fourth across the sand paper. You don't want to be pushing down on it, just let its weight force it down. You should be starting out with coarse and moving up to fine as you lap. Start with 400 or 600 grit (depending on how bad the surface is), and then move up to like 1000 or more if you really want a mirror finish.

Some people go in circles, others back and fourth, but I don't think it should make much of a difference.

While you're lapping, you can check on the surface where you drew on it with the sharpie to see where the curves are, and if it still needs more lapping. You should also wash off the sand paper and HS once in awhile.

Your HS should be fine if you aren't going to OC at all, but if you want to upgrade I would just get a new fan. Probably something quiet.

AS5 is great. Here is a nice guide to help you
http://www.arcticsilver.com/arctic_silver_instructions.htm
Remember, lots of thermal grease isn't the best. Use as little as you can while covering the whole die.

EDIT: you can buy your own sand paper, but sometimes it will be expensive. Insulglass sells a bunch of small sheets for a good price, and includes a mirror finish solution with it. If you go to a hardware store you will have to buy bigger sheets, which might cost more.
 
actually kits aren't that badly priced... They include a piece of glass (flat surface) with various grits of sandpaper. You dont have to go out and buy 4 or 5 packs of sandpaper just to lap a single heatsink (although we all know you'll be lapping a hell of a lot more in the future)... Insulglass on this forum sells kits, but i haven't seen him around lately, try PMing him.
 
I just posted a link to Insulglass' website. He sells a bunch of different stuff for lapping. The basic kit only costs $4 and $1 for shipping. Very cheap.
 
Originally posted by ChingChang
I just posted a link to Insulglass' website. He sells a bunch of different stuff for lapping. The basic kit only costs $4 and $1 for shipping. Very cheap.
ah, i wasn't sure if it was the same guy ;D
 
D-Tek sells kits also, but their kits are rather overpriced for being 6 sheets of sandpaper.

As far as lapping goes, I just use back and forth myself. I found I get a better polish like that, and get better lifespan out of the paper. That's just because I do most of my lapping at work for my co-workers, so i don't carry insane amounts of paper...just what I need.

....and yes, I do have a glass plate at work for this :D
 
Just a tip (that all will surely not agree on)

If your heatsink is flat, but has noticeable machining marks, i generally start lapping at 400 grit, It's just rough enough to take the machining marks out, but it's not too rough to make the job any longer than it is supposed to. Some high quality 220 grits are useful when the heatsink is nowhere near flat, and speeds up the job considerably. I just use the 220 to get the sink flat, but will move up (400-600 range) when actually trying to 'smooth' the sink out. 600 is the same roughness as a worn down 400 grit paper i find, and anything above that doesn't take much off the sink, so it's more useful for smoothing, and not actually sanding down the copper. If you want that really nice shine, flip any of the pieces of sand paper over (assuming you have high quality paper that won't fall apart on you) and use the backside to "polish." The consistency of the back of the sandpaper i've heard is around 10k grit, but i don't really concern myself with it, it does a good job at shining the sink, although the sheen is not what counts in a finely lapped sink. The flatness is what counts.

I also use a back and forth motion, but i realize it wears the edges away (leading edge, especially) more so than the actual center. But then again, i'm not anal, nor a perfectionist!
 
I never get to use the back with my method...I like using near obscene amounts of water to allow the crap to "float" off the paper. That way I can use far less paper and also get an exceptional polishh on top of the smooth lap job.

The bad to this method is the obscene mess it makes. I go through about 14oz of water through the entire lap, andI use up about quarter stack of paper towels....not exactly environment friendly.

Also shows why my glass plate is so big....it's 12x17...actually it started life out as a test plate for a wave soldering machine...then found it's way into my hands when the machine was no longer wanted :)
 
Awesome, thanks for the replies. I think I'll order that kit tomorrow or the next day. Only other thing I'd like to ask is, after lapping is there something I should apply to the copper afterwards to prevent oxidation? I was told most copper HS come with some sort of lacquer on them from the factory.
 
I never add anything to mine, i imagine an extra coating on the base of the heatsink would reduce the cooling efficiency. It's just for looks anyways, there is a bit of discoloration if you get moisture on the base of the block, but if you keep it dry and stored away, it generally retains its sheen
 
Yeah, if your worried about storing the sink, just do it, and use some 1500 grit or higher on it when your ready to use it.
 
Ah, cool. Thanks a bunch. Yeah, i've had it sitting around for about a year now i guess and it'll probably be at least another 2 months until I use it but I want to get the lapping done ahead of time so I'll just do a quick sand down later.
 
Originally posted by mustang_steve
I never get to use the back with my method...I like using near obscene amounts of water to allow the crap to "float" off the paper. That way I can use far less paper and also get an exceptional polishh on top of the smooth lap job...
That's why I use some kitchen soap, it makes it glide real easy and gives it a nice polish.
 
I dunno, but mine didn't oxidize. If it actually does, maybe just use it until the last sheet of sand paper?
 
I didnt read every reply, but if you're not overclocking, you really shouldnt need to worry about lapping your hsf anyway... Of course, if its more efficient, it means you can drop the fan speed a bit for some better noise levels.
 
Another tip, run the volcano 11 without the fan grill, its heaps quieter, and more efficient :)
 
Originally posted by Etacovda
I didnt read every reply, but if you're not overclocking, you really shouldnt need to worry about lapping your hsf anyway... Of course, if its more efficient, it means you can drop the fan speed a bit for some better noise levels.

Unless the bottom looks like a crinkle-cut frenchfry. :p

I got some $5 Al HSFs from SVC that looked like that (vvvvvvvv)... Used 100 grit to flatten them down... Kind of silly that they didn't machine them at least a little better than that.
 
Yeah, i've just taken the grill off. I actually am going to overclock this thing in a year or so once I know i can afford another chip and what not so I'm just doing the lapping now b/c it will need to be done at some point anyway.

Good idea, thanks.
 
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