Lapping Problems - HELP

1kiwi

1kiwi

1kiwi

Soldato
Joined
25 Oct 2007
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Los Angeles
Guys,

I'm using this guide to lap my TT. Unfortunately, I've run into a few problems. My TT is pretty flat, in fact, when i hold a razor blade over it, hardly any light comes through. I had read however, that if you bother to lap you CPU, then your HS better be flat otherwise you shouldn't even bother. So i decided to go forward with it.

Anyways, i started lapping by dripping some water over the 220 wet n dry. I then used a back and forth motion which immediately started to remove the grit from the paper. The HS was also sucking to the paper which is probably why the grit started to come off. From the below pictures, can anyone give me any suggestions.










As you can see, the heatsink has taken the grit right off!!!!! I only have another 3 sheets like this so any advice would be much appreciated!!!!
 
How much, i used quite a bit and it made a mess of the sandpaper. Should the heatsink be pushing water around?

I checked out this youtube guide and he doesn't seem to use water at all! What are everyones thoughts?

Does anyone know of another guide, other than the one stated above.
 
Why did you start with 220 grade? Surely the base wasn't that bad?

Anyway its best to tape the paper down to the glass. I personally don't use water as water is mainly there to stop dust. If you don't want dust then use water and also a little washing up liquid (just one drop is enough) then start again but don't press the heatsink down - let its own weight do the work for you.
 
Thanks W3bbo, I'm doing it inside so i think ill try without water (and see how much dust there is) and then if it's really bad use water. In your experience, how much water is required. Do you want the paper soaking or just a few drops?
 
Looks like the edges of your Heatsink base are cutting the Paper, some good reviews tell you to give the 4 edges a slight Chamfer using heavy Grit Paper like 200 or 400.

This will stop it cutting up your paper, and do not lean too heavy on it, the heatsink will do the work as its heavy on its own.
 
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beh* said:
Cheers. What about when you last lapped a heat sink?

Thanks again guys.

I'm about to have another go in a few minutes.
Click to expand...

As W3bbo says, there's no need to use water. The heatsink will slide far easier across dry paper, especially if the paper is taped down.
 
Thanks helmutcheese. So what your saying is to basically sand down the edges to prevent them from cutting the paper. Also, your picture didn't work. Perhaps you need to add in the URL.
 
beh* said:
Thanks helmutcheese. So what your saying is to basically sand down the edges to prevent them from cutting the paper. Also, your picture didn't work. Perhaps you need to add in the URL.
Click to expand...

Very Slightly so as not to lose surface area.

The picture was of wood lol, just put a small 45degree edge on all 4 edges if that makes sence.

I know some do it wet some do it dry, it will slide with water easier esp is some soap in it (very little), and Paper will last longer.

Paint entire base with a Black Perm Marker let it dry for few secs then drag across dry Paper to see the state of the base.
 
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OK, dry is going well! The technique im using is as follows:

Im using 200 to get it nice and flat. Im using a back and forth motion, and then rotating the HS 90 degrees. So i am essentially sanding in different directions every minute or so. Should i just be sanding in one direction?
 
If you didn't pencil a cross joining the corners at the start, do it now. Also do you have some graph paper to check the reflections are straight?
 
I was planning on printing it out. Allot of people only sand in one direction. As im changing direction ever minute or so, im constantly changing direction. Whats your thoughts ?
 
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