Heat Sink Lapping - A Set of Sandpapers
(Page 3 of 4 )
Before we started the processor lapping the heat sink we collected our tools. A quick trip to the local automotive store got us everything we needed. We picked up a sanding block that is most often used in automotive body work, dust masks, and a variety of varying grits of sandpaper. For this project I used grits ranging from 200 to 1500 in both wet and dry versions.
Taking the heat sink into my workshop I gently placed it in the bench vise. I did this to prevent the heat sink from shifting as I work on it and to hold it securely for the lapping process. Before we started any lapping it is very important to put on your dust mask.
The lapping process causes the creation of microscopic particles of aluminum to enter the air. Inhaling these particles will cause severe respiratory damage and can eventually be fatal. Ideally, a full fledged respirator is the better choice for doing this kind of work but a dust mask will suffice. Be sure to perform this work in a well ventilated area and not on the coffee table in front of the television. Aluminum particles can remain in the air long after you’ve finished your project and its best to do this work in a low traffic area.
The first grit of sand paper I used was the 200 grit paper. This is a dry sanding paper and, after I attached it to my sanding block, I set about lapping the heat sink. A question often asked about lapping a heat sink is whether a back and forth motion, a circular motion, or a single direction motion is best. The simple answer: all work well. However, if you long for a mirror-like finish on your heat sink it is best to use a back and forth motion.
After the first pass with the dry sand paper the heat sink was looking a little better but still needed more work. Once I was satisfied with the 200 grit paper, I was reading to move on to the 440 wet sanding paper. Wet sanding is the process of using specially made sandpaper’s combined with water to sand the surface of a given area. Wet sanding paper often feels especially smooth to the touch and are used for fine polishing work. The higher the grit; the greater the polishing. However, the higher grit wet sanding papers are meant to be used after lower grits as their ability to remove deep gouges is very minimal. The 200 grit smoothed out the heat sink at an incredibly fast rate and with each successive grit of paper I will not be smoothing out the bumps and crevasses as much as I will be polishing the aluminum which is better for heat transfer than a dull surface.
As you can see the differences from the 200 grit dry sandpaper to the 440 grit wet sanding paper is quite dramatic. Before I started the next step of wet sanding with my 1000 grit wet sanding paper I made sure to clean the heat sink. The black watery residue from the wet sanding contains the aluminum particles and I didn’t want these particles to sand the surface further than I intended by not removing them. After I was finished with the 1000 grit paper I wiped the heat sink clean again and used my final sheet of 1500 grit sand paper.
Next: Finishing the Shine >>
More PC Cooling Articles
More By Remco Degooyer
