Lapping

[n00b 0f l337]

Anyone got any advice on lapping and where to get the correct sandpaper? (And what sandpaper)

[martinjon666]

i use automotive wet/dry sandpaper, i have heard different opinions on how high of a grit you need to go, varying from 1200-2000. Go to autozone or checker or somewhere and get their sandpaper, start at like 200 or 400 and work your way up to 1200-2000. Work in the same direction, side to side for a bit, then turn it ninety degress work in the opposite direction, should take between 10 and 20 minutes to get a good lappy.
Hope this helps, this is just the way i do it :)

Jon

[[XC] moddolicous]

Cathar posted a guide on what he thinks is the best way to lap:

Well in the hunt for the best die-baseplate thermal "connection" with my waterblock research, I've found the "best" method that I've been able to achieve, and it falls in line with what's accepted and been tried elsewhere. However, me knowing me, I don't believe stuff until I try it for myself.

Basically I've lapped bases with:

150 grit
220 grit
320 grit
600 grit
800 grit
1000 grit
1200 grit
1500 grit
brasso + strong cloth
toothpaste + cloth
fine-cut cleanser
jeweller's rouge

All in incremental steps, to varying degrees of finish from rough, to a copper finish you can shave in.

So what's worked out the best?

Go to Bunnings. Grab a small board of 12mm thick MDF (Medium Density Fibreboard). It's flat as glass and a whole lot cheaper. Should cost about $5. Pick up 1 sheet each 150grit, 320grit, and 600 grit wet'n'dry sandpaper (black colored).

Take your heatsink, and lightly scribble over the base with a black permanent marker. Color the whole base in if you want.

Stick your 150 grit paper onto the MDF.

Take your heatsink/waterblock and scrub lengthways (if the block has a longer length in one direction - otherwise just pick). Move the block up and down the sandpaper while pushing down firmly. Do not move in a circular motion, just straight up and down. You'll need 3 hands. One to hold the block, and two to hold the edges of the sandpaper down so it doesn't "grab" and fold and rip. If nature didn't supply you with 3 hands, sitting on the floor and using a foot works just as well. Keep scrubbing until you can't see ANY of the ink/black. I periodically look at the base to see how it's going, this is how I can tell if a block is initially convex, concave, or whatever. This can take anything from 1 minute to 30 minutes (or more) depending on how flat the base is to start with.

Once the ink is gone, use the 320grit and scrub cross-ways. This time keep doing it until all the cross-lines left by the 150 grit sand-paper are ground away. Just move the block straight up an down - no round motion. This should take about 3-5 minutes.

Then use the 600 grit sandpaper and moving straight up and down lengthways sand the base until the 320-grit cross-ways lines are gone (another 3-5 minutes).

Finally follow up with a circular grind of the base on the 600-grit sandpaper for about 30 seconds. Wipe clean. This should leave the base with a dull reflective surface.

You're done!

Like I said, I've tried anything from 150-grit up to a mirror polish, but the dull 600-grit finish works out the best. Surprisingly, a 220-grit finish, and a mirror finish give about the same results (at least for me), while the dull 600-grit finish gave me about 0.5C better than either of those two for a ~100W CPU load.

I know that the above has been said here before a few times, so consider this as a re-affirmation of the procedure.
This shouldnt differ for sub-zero cooling.

[Revv23]

glad cathar's guide got posted here, i sand with 600 grit and i catch crap for it not being as shiny as some people's brasso jobs, but i get the job done cooling wise :)

[cryo-tek]

I used 400 and 600 wet/ dry from the auto parts store. I also picked up a granite tile to work on. Wet the tile so that the sandpaper will stick and keep the grit wet while sanding. To check if the head was flat, I’d push it down on the sandpaper and twist the head. Then look at the sanding pattern.
If you want the shine hit it with something like Semi Chrome or Brasso after.
:toast:

[Revv23]

cryo is catching on quick :toast:

[epion2985]

From what I understand polishing to a mirror finish does nothing for preformance. And possibly the opposite, with all the chemistry you are depositing on the copper as you polish it.

[jinu117]

From what I understand polishing to a mirror finish does nothing for preformance. And possibly the opposite, with all the chemistry you are depositing on the copper as you polish it.

Yeah you really need to clean up after polishing. I use artic cleaning stuff ( i think it is just goop off thing with nice cleaner for 2nd stage lol... certainly smells like it, or electronic contact cleaner).... Thing shows so much deposit on goatskin I use to clean that I usually have to do it twice.

[Revv23]

artic cleaner is pretty sweet, i usually use acetone then alcohol to finish, but from what i herar artic definetly requires less elbow grease

[billb]

Anyone got any advice on lapping and where to get the correct sandpaper? (And what sandpaper)http://easypckits.com/

[johann]

Cathar posted a guide on what he thinks is the best way to lap:

This shouldnt differ for sub-zero cooling.

This guide is overkill imo, I use 400grit, 600 grit, 1200grit and 200grit and get a near mirror finish every time and performance is great.

[ayrtonsenna]

getting it flat is all that matters.......shiney looks good though!!!!

[johann]

getting it flat is all that matters.......shiney looks good though!!!!

True, the only reason I actually lap to shine

[Revv23]

This guide is overkill imo, I use 400grit, 600 grit, 1200grit and 200grit and get a near mirror finish every time and performance is great.


how is cathar's guide overkill? you do more then he does! :p:

skip to the part where he says what worked the best, and he says 150>320>600 and you are done. 600 grit is the most you should go, after that performance gets worse.

[johann]

Sorry I did not read the whole post hehe.

[Blaster]

wet sand paper

start at 400, 600, 800, 1200, 1500, 2000

always keep the sand wet and clean, need to be carefull on final steps to achieve mirror finishing

[n00b 0f l337]

I just need flat, I Dont feal like losing my arm over a mirror finish that I will never see. And still best place to buy these sand papers? Wet or dry?

[Blaster]

wet

any place that sells paint to cars will have all the sand paper you need

[ozzimark]

I just need flat, I Dont feal like losing my arm over a mirror finish that I will never see. And still best place to buy these sand papers? Wet or dry?
sears, lowes.. you name it, if it's a half decent hardware store, it should be there :p:

[n00b 0f l337]

Homedepot?

[Sume4]

Propably yeah. Although there are no Homedepots here in finland.

[quintus]

I finish with 1200grit and i'm happy. Read somewhere that 800 is the best but the ppls nowadays look for bling bling:stick:

most important get it flat before mirror

[ICE COOL]

hey dude i lapp my evaps with ice skating stones. that are ferry fine stones.

ICE COOL

[epion2985]

I finish with 1200grit and i'm happy. Read somewhere that 800 is the best but the ppls nowadays look for bling bling:stick:

most important get it flat before mirror

well acording to cathar most important is to stop at 600 and call it a day, as it gets worse not better from there on.

[eBoy0]

Mine turned out quiet nicely.

[Jonas]

guides:

http://www.overclockersclub.com/guides/heatsinklappingguide.php#
http://www.tweakers.com.au/articles/cooling/lapping/page1.asp
http://www.water-cooling.com/reviews/lapping/lappingkit.php
http://www.systemcooling.com/heatsink_lapping-01.html


a smooth surface is more important than a mirror finish