To Lap or not to Lap
 

Well I'm gonna spend this weekend putting together my watercooling rig and have a question about the cpu and video card block ( Maze2 and gf block from DD).

I read a debate on this forum about lapping might cause the temps to get worse. Should I just leave them as is from DD and go for it or get out some 600 grit?

Lap it!
And if it presents irregularities (visible to your eyes), start at 400, or even 200.

lapping is good start low with 400 move higher as you see the block flatning and end with 1000 remeber you want the block flat so u want to put the sandpaper on something flat so some a peice of glass will work or if your lucky u might have a glass coffey table you can use :) wow did anyone noticed I didnt you any . , in that post? one nice big blah

If it isn't tarnished, and looks smooth, I probably wouldn't bother, DDen's stuff is normally quite good, in this respect. I doubt you'd get more than 1 or 2C differance, although you can always try

I strongly agree with Brad...
if you want to give it a try, don't lap it too much though... because too much lapping can reduce performance... arctic silver compound needs micro gaps on the surface to fill in, otherwise won't work...

Bruce

Well, I can tell you that my Maze2 was everything but flat, took me two hours of lapping to get it somewhat good..

Lapping will not decrease peformance. If you get it so smooth, then don't use AS2. Its thermal conductivity is only ~1/50 that of pure copper. The reason we use thermal paste at all is because its too difficult to perfectly lap a sink.

Furthermore the kind of lapping we are talking about here with sandpaper and a piece of glass is fairly crude. Take it to a shop or lab and they can smooth it down to the equivilent of many thousands of grit with solutions and real equipment.

No good. Read Dacooltech post.


Agree. However, we can't ask for near perfection and low prices. I received a Maze1C that had imperfections quite visible. It took ~1hour to lap it so it would look almost like in the pics on their website. When I received it, it was far from this look (tarnished and irregular). When I started lapping on a piece of glass (plus the sandpaper, of course), it started shining only at the peripherie, showing slight but obvious warp. I was at 600 grit, I started back at 200, 400, 600 and 1000 and got it flat and shiny.
At ~$40 the water block, we can't ask for aeronautic machining. This is not criticism to DD, I am using their hardware sincer 1 year without problem. Great stuff.
I prefer paying $40 and add 1hour of my work, rather than doubling the price of the block. This is a hobby anyway, I don't count my time.

Just take a 600 grit anspaper, and start lapping it gently. If it start shining on all the surface, then you are OK. If it shines only in the middle, or only at the periphery, go back to 200 grit and lap this baby!

ok i went to the hw store and got some sand paper. just wanna make sure it is the right stuff.

i got all same type in 200, 400, and 600 grit.

iy is made by norton.

it says wet sanding.

looks black in color.

Sounds about right, but I prefer 1200 and 2000 as well for the mirror shine effect :)

Ok so now I'm gonna kill everyone here with a modem:

Before I started (Tarnished :))

http://www.procooling.com/~iceheart/before.jpg

180 grit:
http://www.procooling.com/~iceheart/180.jpg

320 grit:
http://www.procooling.com/~iceheart/320.jpg

600 grit:
http://www.procooling.com/~iceheart/600.jpg

1200 grit:
http://www.procooling.com/~iceheart/1200.jpg

2000 grit:
http://www.procooling.com/~iceheart/2000.jpg

And this picture shows that there is indeed LOTS of micro-irregularities for the AS to fill:
http://www.procooling.com/~iceheart/2000_scratches.jpg

And everyone with a small screen resolution :)

to anyone that is interested to know, that isn't his camera :P

SO, are you swedish or are you just someone who likes swedish bills?

The hw store i goto doesnt have over 600 grit size.....damnit.
But do you agree 600 is good enuff for thermal transfer?

Actually I've read that >600grit leads to higher temps, I highly doubt it, but I'd say that 600grit is good enough... But you won't get that mirror finish, that's for sure.

yeah he is in Sweden.

If you want some fine sand paper, Tamiya does some up to 1200 grit for modelling purposes. Most hobby shops here carry it

Ironic, I just lapped my Maze2 this afternoon. It did have small mill marks.

I am glad I did lap it, it was already shiny but, it had a slight low spot where the CPU will contact the water block. Didn't even notice it with the straight edge upon inspection.

Started with 320, 400, 600, 800, 1000, 1500 and 2000. Took me longer than it should have since at the 1500 level some junk got on the paper and scratched the block and I had to go back to 400 and start over.

I was wondering if AS2 or AS3 would be less effective is the surface is too smooth, interesting you guys bring that up.

Jim

Even with a highly lapped block you still need a thermal paste to fill the microscopic surface impefections. Take a look at Thermal Interface Basics. Even the best thermal goop (Arctic Silver 3 of course) has some thermal resistance. Improvement in temps with a highly lapped surface is because less thermal paste is required so the thermal resistance between the block and CPU is lowered.

If you want to improve your lap job, clean the block with water and do the final polish with a fresh sheet of 2000 grit wet/dry paper and Arctic Silver as the lube. Any time you lap, there are going to be some copper and abrasive particles left in the microscopic suface imperfections. Using Arctic Silver as the final lube will add some Arctic Silver to the mix and your temps will drop.

OK so what u r saing is to rub a thin layer on the bottom of the block then sand w/ 2000 grit paper? Sounds like a good idea? After each level of sanding, with what do you wipe the block off with?

If I do stay with 600 grit as max would you still recommend using as2 or as3 as the lube? In that case after you wipe the block off you would not need to do anything else to the block right? Just clean off core and apply the block?

Perhaps one of you or all of you could post a quick tutorial of lapping from the start to the finish. Pictures would be very helpful.

never heard of anyone using AS as a lube, but it sounds like a good idea, I'm going to be lapping some blocks soon, so I'll have to try that

I have never used AS2 for a lapping aid, but I do rub a drop into the HS/Block base at contact point then wipe off the excess with a soft cloth before installation.

Jim

Yep, I'm in sweden.

And always do the 1000 and 2000 (at least) with brand new papers, it sucks if it's "spent" or there's some crap on it that makes some nasty marks on the bottom

So.. I'll take this part in 1337 encrypted lang :D
Var hittar du papper över 1200grit?

Jag köpte mitt på Bauhaus i malmö... men det borde finnas i bilaffärer och liknande. Även på de flesta andra byggvaruhus.

Ahh..... I see, so thats why... NAaa, just kidding with you guys, kinda fun that you don't understand a word.

Tackar, har ett bauhaus rättså nära här också..(Helsingborg)

[1337 lang]
aha bauhaus måste dra dit nån gång....
bauhaus[uppsala] såklart!
ska nog ta o slipa ner min P4 samtidigt som jag kör min swiftec MCX478. får se om man får någe bättre temps sedan....