Hoot was kind enough to send this to me here you go
Mornin' Doc;
The "Hoot" technique is fairly simple. You pick up a sheet of Wet-or-Dry 600 grit silicon carbide paper. Take a coffee cup (clean) and put a couple of drops of dish liquid soap in it. Fill it up the rest of the way with water and stir it to mix in the soap. Find a flat surface. I prefer to use a formica counter top, preferably near the kitchen sink. Wet the paper under the spigot, both front and back sides and plop it down on the counter. If possible, remove the fan from your heatsink and restrain the clip with a rubber band or twister seal so that it does not drag on the surface when you set the heatsink down. Pour some of the soapy water on the sheet, enough to make a puddle on it. Set the heatsink down in the puddle.
Now, depending upon how bad the heatsink base finish is, grasp it firmly and slide it around in a circle while bearing down on it in a constant fashion. You will feel the grit bite into the finish. Move it in that circular motion slowly. If it seems to form a vacuum and bind to the paper, then you're pushing down to hard on it, or you are not using enough of a puddle of water. There is a delicate balance between how hard you press down and when it starts to bind. You'll get the feel for it fairly quickly. After you have moved it in a circle for a while, you will see small copper or aluminum particles in the puddle. Stop and put the sheet under the spigot to rinse off the "slurry". Put it back down and pour more soapy water on it. Rotate the heatsink 90 degrees. Re-grasp it and continue the motion, inspecting the base every minute or so. As the base finish improves, you use less downward pressure and faster circular motion. Don't go so fast that you lose control over how flat it sits. You don't want it rocking. It helps to grasp it as close to the bottom as possible. Remember to stop frequently and rinse off the paper, applying yet another puddle of soapy water after each rinse. The paper will slowly lose the aggressiveness of its bite. That is normal wearing. Continue until you don't see any improvement in the finish. The goal is to get it flat and smooth. Even though you will see fine "spider web" scratches remaining, you should not be able to feel them with your fingernail. By the end of the process, you will not be bearing down at all and moving the heatsink as fast as you can, kind of like waxing a car.
Though it takes a while to read this process, it's really not complicated. It is definitely a learn-as-you-go process. Obviously, the more heatsinks you lap, the more natural the entire process feels.
Know when to quit, step back and admire your work. Rinse off the paper and set it somewhere to dry. Yes, you can reuse it several times, depending upon how bad the finish is on a heatsink. Ones that don't need much lapping get the oldest sheet of paper. Ones that are in real rough shape get a fresh sheet.
Good Luck
John "Hoot" Hill
