Do I have the right tools to lap my heatsinks? Lapping guide?
 

I have bought 220, 320, and 600 grit water-proof sandpaper (only kind with the right grits at my local hardware shop). Will that be sufficent to correctly lap an aluminum and/or copper heatsink? I also picked up a 1' by 1' sheet of glass and plexiglass to use as a hard, flat surface for lapping (I am not sure which would work better, glass or plexiglass so I got both). I also obtained a 1" by 1" square of glass and plexiglass to wrap the sandpaper over again for the purpose of having a hard, flat surface.

Do I have the right tools to get the job done?

Also, what is a good lapping guide?

There are many lapping guides available, but yes, you have everything.

One note: the piece of glass is great, but the reason that glass is usually advised is that not only is it cheap and easy to find, you can also look at a reflection over it, to determine if it is indeed flat: watch out for bumps (fault in glass).

I would avoid the plexi. The glass plate might be flat. You could get some thicker plate glass, as that is ground flat most of the time (not always the case though!). An (better) alternative would be a granite plate (cheap surface plate from enco/grizzly, or just try to find some crap).

All depends on how flat you want to get it... the glass you have might be perfectly ok for your purpose :D

I have found that the 1" by 1" glass piece is way too big for my purposes. I don't think my fingers can do a good job keeping things flat so what is a good object to use for sanding small areas?

I believe the preffered method for lapping is putting the wet sandpaper down upon the big sheet of glass, and then rubbing the heatsink on that.

Hold up a sec. You might want to try some other stores for finer grit sandpaper. 600 grit is still very coarse, possibly more course than the machining that is already on my the heatsink. And if you start at 200-300 grit, you might actually gouge the heatsink, which is what your trying to remove in the first place.Walmart sells 1000, 1500, and 2000 grit wet/dry papers in their auto section, and most auto stores like advance auto or autozone have a fine grit sandpaper selection near the paints.

Use some soap too, it will help the heatsink slide easily, and wash the sandpaper off and rewet it to keep it from clogging.

also grip the heatsink as close to the bottom as possible, so as to prevent wobbling and messing up your lapping job. and try to move in a circle or in a figure 8 motion, and rotate the heatsink periodically to prevent taking off too much from area.

just wanted to double-check that your are moving the heatsink over a piece of wet sandpaper, stuck to a piece of glass. Do not put the heatsink in a vise/do not clamp the heatsink and try to move the flat piece of glass/sandpaper over it. The idea is to make the heatsink as flat as possible, so lots of light, repetitive strokes are better than a few heavy strokes, which might not be perfectly parrellel to the heatsink.

Post back if you have anymore questions.


later
sean

edited for spelling

I like to start at 240 grit to get things flat, then work up to 1500 grit personally.

A squirt of soap on the wet paper I find helps keep the heatsink moving smoothly.