Look at this SK6...does it need lapped???

[PDL]

Just got this today and I am very impressed with it and I don't even have it installed. I am impressed with the workmanship.
I carefully took it out of the plastic bag taking care to not touch it with my fingers but with a paper towel and placed it on my scanner to take a pic.
After scanning at 350 dpi color, I could see the ridges left by the machining. Running my fingernail accross it verified the ridges are quite pronounced so I guess it could stand some help. I remember reading some other posts about doing a lot of lapping on these things.
Sure looks pretty though!!
Gonna try it with the delta 80cfm fan but not for long....the noise they say!!
I really want to see how well it does with the cohesive air cooling setup.

[Monaco]

well, if you can actually feel the irregularities, then you should probably flatten that bad boy out.

I believe lapping really means to sand and polish something down to a mirror finish. This is a waste of time, unless that 1/4 of a degree is really important to you.

BUT just smoothing out the bottom until it is flat will make a noticealbe difference, depending on how bad it is.
I never go beyond 600 grit sandpaper on my HSFs, BTW.

Of course a shiny, reflective, lapped HSF will look pretty cool.

[Super]

It is a waste of time if you don't do it properly. It actually helped some people drop over 4'C.


Here is a guide. (http://www.wildandyc.co.uk/lapping.htm)

[outhouse]

I would definatly lapp it, if you can feel small ridges with your fingernail then it needs to be lapped, if its flat [which is the important part] you can start with 400 and then move to 600 grit use soapy water to sand with as copper rubs off quite quickly. As far as how far to lapp there is a large debate always going on some say 600 is plenty as it leaves enough ridges for thermal compound to do its job correctly the others end up around 1500 with simular results but with a pretty smooth surface, ive heard of one guy who just polished his HS without lapping and had a 2C difference from 600 and 1500, personaly I would always lapp to ensure that your HS is flat but remember everyone gets different results but I would say that 99% of the people who lapp do see a few C drop in temps and if you use a good thermal compound you may see a few more C dropped of your total.

[Warlord2]

I lost 4c with lapping to 1000

however my heatsink was in very bad condition and wasnt even flat

[Monaco]

I didn't explain what I meant very well at all, I'll try it this way-

Take that SK6 and sand it on a flat surface. Start at 150, then 220, then 300 to 400 to 600 grit sandpaper. That is what I do to my HSFs all the time and it makes a big difference in temps (depending on how "unflat" it was, you might get even more than the 4' Super mentioned). It'll be a little reflective. Call this Step 1.

Do all that and then go to wet sanding all the way to at least 2500 grit abrasive cloth, in the smallest grit increments you can get. When it reflects without distortion, yer done. Call this Step 2.


Goin all the to Step 2 is what my shop teacher taught us was how to put a high polish on metal, he called it lapping too.

In my experiencethetemperature diff between step 1 and step 2 is almost nil, if it is even measurable. Things like perfect application of grease and mount pressure become more important. So I always do step 1 but I leave Step 2 for when I want to show off.

Of course- the whole idea is to make the 2 mating surfaces totally flat, so going nuts on it will definately help. Just not so much.

I think maybe I'm just getting too anal about semantics here. Lap, sand, whatever you call it- just abrade that baby smooth!

[CrystalMethod]

Going to a really high polished finish will only help if it's lapped FLAT. I have a pane of glass I use (I can't remember what type, but it's not "regular" glass). I also have acsess to measuing tools that can check to see if it's flat to within 1/10 000th of an inch. With out being able to make sure it's completly flat, i'd only go up to 800 Grit.

[Monaco]

That's an awesome point to bring up, CrystalMethod. A flat surface is probably the most important part of the deal.

Also you have easily the best sig on planet earth.