When I lap a heatsing iperfer to use a piece of glass, I t gives a nice solid flat suface, but anything that is comparable can be used. For sandpaper, I go with the wet/dry kind. The silica kind is best, cause it dont wear out as fast. For grit there is lots of leway, and controvesy on how high to go, and what grits to use. I went with 600,800,1500, using even pressure. Cleansing every-so often with water to keep the paper clean. Don't forget to clean the HS with a towel, paper/ cloth (up to you, i perfer paper). I heard you can use washsoap to lube it as it will not sand as easily (it will stick) without it. If you use common sence it will come out really nice and polished. Things to watch out for... not getting an even polish, and unlevel results. Try to rotate the work bout every 25 or so up and down motions. Keep an EVEN pressure as you can. I used the wieght of the HS. On the direction of sanding, I went with the up and down strokes (forward and back). Rotating the HS 90° every 25 U/D motions. If you understand how to sharpen a knife then you get the idea. Get it smooth with the lower grit, smooth it with the mid grit and finish with the high grit. The high grit will be the longest part, since you are just using the lower grits to prep for the finishing polish.
Copper sands much faster than aluminum so keep that in mind, if you have a composite metal (two metal) base. And dont oversand/polish, since you are taking material away from the base.
One method I have pondered was how to speed up the process, I threw that idea out, my last lapping cost me hour of back and forth, rotate, back and forth, rotate. Boring and yet can mess up a HS if not done right, but if it is done right, you get really shiny HS that you can see yerself in, and remove any inperfections during the machining of the HS. Result... A cooler CPU, and sore arm. If this is not detailed enough try this link.... This process has been been around a long time now.
http://www.fury-tech.com/modules.php?mod_name=Contents&jump=lapping
I wonder If a person can use rubbing compund?
What does the base of the HS feel like at load temps? Is it hot of warm?
