Lapping Question

Hi,

I have been lapping now for about 20 mins and the botton feels smooth to the tought, and even when I run my fingetnail down it I doni't feel any large gouges. But if I tilt the bottom of the heat sink into the light I can see the entire thing is scratched up. Is this ok? In fact I don't see how it can ever not be scratched up because after all we are using sand paper. I am using 600 grit paper.

Thanks.

Hi,
Welcome to the forums!


actually you just need it to be flat. but I'd recommend you to continue using all the grifts up to 1200/1500.

I tried looking for grit up to 1200 and could not find it anywhere. Even the guys at home depot(a large hardware chain in the us) never heard of such a high grit. Where do I get such high grit sand paper?

contrary to popular belief anything higher than a 600g is almost useless. anything higher and you attain more of a lustre. this does not help cooling. the objective is FLAT and SMOOTH. there are a few techniques that others here in the forums might suggest. i have not tried it but i will when i get another chance. that is to mark the bottom of the heatsink with some sort of marker. as you lap the bottom of the hs the mark you made will and should evenly go away or be sanded away. this is a surefire way to tell if the bottom is flat.
remember, FLAT and SMOOTH.

Lub said:

I tried looking for grit up to 1200 and could not find it anywhere. Even the guys at home depot(a large hardware chain in the us) never heard of such a high grit. Where do I get such high grit sand paper?

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I picked up some at Kragen Auto. They use it for buffing new paint jobs on cars or somesuch.

Yeah auto shops will have higher grit sandpaper with paint and dent repair stuff.