Hello I was just thinking about how many people on this site use sand paper. Then I was thinking about how much sand paper I have. (allot) One day I decided to lap my heatsink so I went to buy some sand paper and once I got back instead of buying just a few sheets I realized that I had bought a bulk lot of the stuff. Nice sanding job, but no selling until you have 75 posts, and no ebay pimping please, read the rules - wonka This is a few pictures after I was done wet sanding through 400,800,1000,1200,1500,and 2000 all by hand. and one of the many, many, stacks of sand paper.
That looks awesome. Did you just use the wet sanding paper, or did you use some polishes aswell? I really want to try this, but if polishes are needed to reach the desired affect I will be put off somewhat
I only used wet sand paper up to 200grit with soap and water and a sore arm. I was laping my first sink so i was useing a cheapo i had laying around. but i did get about 2 degs cooler.
i forget which article it was but actually going to a mirror finish like that actually causes a bit of a increase in temperatures compared to optimal conditions. IIRC about 600grit to 800grit ends up being as close as possible to optimal conditions for heat transfer through metals. I could work up the thermodynamics of it but to be honest I’m too lazy. to put it in a simple way the problem you end up with by getting such a good finish is that heat needs a bit of turbulence to work at max efficiency. by creating a surface such as this it might be better than stock but not optimal.
Ive just had to lap my HSF because the serface on its was absolutly discusting and i wasn't going to put it on the cpu.
Looks nice. It's important to remember that flatness is far more important than smoothness. After around 400 or 600 grit, you really start to hit diminishing returns. Anything higher doesn't do much but look pretty. I have a bunch of old Pentium/Cyrix/K6 CPUs lying around. Some are fairly big and useful, despite having large, spaced fins. They still have a lot of surface area. But the bottoms are bumpy to the naked eye and by touch. You can literally see rolls in the material opposite the fins on the other side, it's gross. Then again those things didn't need much cooling, so it's understandably cheap.
I would think that a 800 grit would be optimal due to the surface area for the thermal grease to transfer heat through. But the shine looks really pretty...great for asthetics.
