Vasto Posted July 9, 2009 Posted July 9, 2009 (edited) Hey everyone, it's been a while since I posted but I just built a new computer (i7 920) and am in the process of putting it together. I was wondering how much to lap the heatsink. I've heard that making it too shiny is actually detrimental to the heat transfer. What is the recommended grit to go up to? This is on a stock cooler because I currently don't plan on overclocking it too much. (I'm sure hackintosh will cause enough problems for me.) Thanks, Vasto EDIT: Also, how would Scotchbrite work for lapping? I used it on a copper pipe and it seemed very fine. Either way I'm going to an automotive paint shop tomorrow for sand paper because of other projects. Edited July 9, 2009 by Vasto Share this post Link to post Share on other sites More sharing options...
rourkchris Posted July 9, 2009 Posted July 9, 2009 http://forums.overclockersclub.com/index.p...c=71649&hl= This really helped me out. Share this post Link to post Share on other sites More sharing options...
hardnrg Posted July 9, 2009 Posted July 9, 2009 it isn't the shininess that's the real aim... flatness to maximise the contact between CPU and heatsink is the aim... shininess and reflectivity are by-products and can help judge the flatness you shouldn't use polishing agents really, wet 3M (or similar) sandpaper like 240, 400, 600 is about what I'd consider the minimum... 800, 1200 help a bit more... 1500, 2000+ is more for aesthetics and doesn't really gain any cooling performance... you can get all of these grits at good automotive stores, even the higher ones the only polishing agents I would recommend are industrial grinding powder for lapping... not household cleaning or metal polish products... think grinding compounds with grit ratings rather than polishing sprays or liquids grinding compound would really be if you wanted a mirror finish, and would only really make sense if you are producing your own custom waterblocks or something, and want a special finish Share this post Link to post Share on other sites More sharing options...
Crazy_Nate Posted July 10, 2009 Posted July 10, 2009 Share this post Link to post Share on other sites More sharing options...
Verran Posted July 10, 2009 Posted July 10, 2009 nrg is right on! Shininess is just for show. The main thing is to sand in stages to at least 1200. 1600 is better, but not by much. 2000 is pretty much just for show. Share this post Link to post Share on other sites More sharing options...
ccokeman Posted July 10, 2009 Posted July 10, 2009 I have not seen a real tangible benefit past 600 grit Share this post Link to post Share on other sites More sharing options...
RHKCommander959 Posted July 10, 2009 Posted July 10, 2009 I have not seen a real tangible benefit past 600 grit yup. much past thats only for a degree or so. just make sure that when you lap you use a flat surface for your sand paper, like glass. you want the things you lap to be virtually flat Share this post Link to post Share on other sites More sharing options...
Vasto Posted July 10, 2009 Posted July 10, 2009 Are you guys wrapping the sand paper around the glass? And thanks for the grits. When I go tomorrow I'll pick up an 800 and 1200. :-) Share this post Link to post Share on other sites More sharing options...
Baulten Posted July 10, 2009 Posted July 10, 2009 When I lapped my stuff, I taped some sandpaper down to the top of a minifridge. Then you just go over it a few times in each direction and move up a grit. Let the weight do the work. Course, I couldn't lap my Xigmatek much, due to the HDT design. Share this post Link to post Share on other sites More sharing options...
hardnrg Posted July 10, 2009 Posted July 10, 2009 Sometimes I tape the corners of a 1/4 sheet on a heavy (thick), and flat (perfect reflection) mirror... Other times I just wet the paper and encourage it to lay flat lol... I use a drop or two of dishwashing liquid (stuff for in a sink, by hand) to make the water more slippery The method in the OCC lapping guide is spot on IMO... except I do many, many more passes, and take 1-3 hours to lap whatever I'm doing... depends what it is as to how much lapping I feel is required (concavity, plating, surface roughness, level of heat transfer, etc, etc) Share this post Link to post Share on other sites More sharing options...
Crazy_Nate Posted July 10, 2009 Posted July 10, 2009 I just lapped my TRUE last night...took 3 hours. I didn't worry about finish, just flatness. It was pretty horrible to start with (very convex). I really wish I had more lower grit sandpaper (I started with 400 grit wet/dry, but I wish I had 200). The copper tends to gum up the sandpaper, as does aluminum. Just take your time. Going to quickly will cause the edges to catch and the heatsink to rock. Not so good for flatness. If I had to do it again I would go 200, 400, 800, maybe 1600 (if I wanted it really smooth). TIM is going to fill in the microscopic gaps, anyways... Share this post Link to post Share on other sites More sharing options...
Vasto Posted July 10, 2009 Posted July 10, 2009 (edited) Where is a cheap place to buy sand paper? I just went to Sherwin Williams Automotive and they wanted $40 bucks for a pack of 50 sheets. :-O EDIT: 1000 and 1500 grit. Edited July 10, 2009 by Vasto Share this post Link to post Share on other sites More sharing options...
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