lapped...looks kinda strange.

[plague]

Well I tried my hand at lapping the other day. went up to 1500 grit paper. The problem is, the base has what looks like a really rough part in the middle. It's still very mirror like, and doesnt feel any different than the outer part which looks fine. My temps went down about 4 degrees, also. I'm just wondering if this is normal.

Sorry, dont have a digi cam. This is also exagerated:

[windyridge]

keep on lapping the sand paper hasn't hit the center yet when all is shiney then it's done

[Yodums]

Heres my suggestion going through all the hassle again.

Seems your heatsink has a bad surface.

Get 2 sheets of 200 grit and then do it until you see the bottom if as flat then you move on to 400 and so on.


You've just lapped the out side of the heatsink.

Don't get the idea of just start lapping the inside because then it will be more uneven because now nothing is on one surface.

[Yodums]

By the way take a blade and then put it over the heatsink you'll see light come in where you see the paint you did in the center.

Good Luck.

[plague]

I was sanding a long time, the center is shiny and smooth, it just has like a smudge on it. The smudge also wasnt there before I lapped it, and I lapped and lapped, and it wouldnt go away.

[Yodums]

Originally posted by plague
I was sanding a long time, the center is shiny and smooth, it just has like a smudge on it. The smudge also wasnt there before I lapped it, and I lapped and lapped, and it wouldnt go away.

After lapping it did you touch it?

Clean it up with rubbing alcohol?

[plague]

I only touched it after I saw this odd mark on it. It doesnt feel rough at all, it feels the same as the outer edges, which are nice and shiny.

[Diggrr]

Don't press so hard when you are lapping. Some hsf bases can deflect/bend so the results are uneven. Yes it's metal, but it will bend and flex enough to do what yours did. Also, don't squeeze the fins/pins, that can do it too.

Try going back to around 160-200 grit, and work your way back up...just cupping the hsf in your hand enough to keep it moving. It's even better to hold the edge of the base, not the fins.

[Yodums]

Well I suggest you go through it again since you have no idea what it is take my lapping advice:

Start with o

Two 180, 200 or 220 grit and then keep sanding down the thing till everything is flat do not move to another sandpaper grit until everything is all sanded down to one level.

Once everything is flat go 400grit for about 5-10 mins then 600, 800, 1000, 1500 and 2000 if you really want it with mirror and smooth, obviously spending 5-10 mins on each sandpaper.

I'm guessing your aware to use wet waterproof sandpaper.

Take off the fan on the heatsink and remember to wet the heatsink and the sandpaper every 30secs.

Do the lapping on glass, since you need very flat surface. Rub in a figure 8 of up and down motion.

You should be patient when going through this best to do it when watching tv since your mind is sort of on something else and you won't rush the thing so much.

Once your done lapping let it dry and then before using the heatsink rub the part you lapped with alcohol.

Clean the blade of a razor blade with the alcohol lay it on the base and shine it to the light and then you should see no light and you should see yourself in the heatsink.

Good Luck
Have Fun.