DH Guide: Lapping a Heatsink

Discussion in 'Reviews & Articles Discussion' started by HardwareHeaven, Jan 6, 2004.

  1. Roadee

    Roadee Never forgotten

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    Well........I guess some of your statement is true......if you use a cheap polish! I prefer to use Wenol. Reason being, is that it is high quality, used extensively in manufacturing that concerns chrome and other soft metals. It doesn't take long to get the desired look. Easy clean up, and it protects the metal from tarnishing, and with copper this is a plus. If you lap your heatsink properly, and clean it with rubbing alcohol real good.......then make sure that it is dry and use rubber surgical type gloves when polishing........then there wont be any crevices for the polish to fill. Of course doing it this way is pretty anal......

    As far as temp differences.....on an aluminium heatsink. Lapping with up to 1000 grit will drop the temp......let's say for example......8 F, on a cheap one, work up to 1500 and you will gain maybe 2 F more.......polish it and you may gain nothing or maybe 1 F......but if done right.......you wont lose anything.....polishing correctly will take what little pits there are.....and make them even smaller. The smaller the pits.......then the more surface area for heat transfer.......and the less thermal compound is needed.

    Alot of top heatsink makers lap by a machine........and then polish the base with a buffing wheel.......by polishing they are protecting the raw metal surface and it gives it the appearance of being lapped better than it actually is. And that saves them money in machine work. Think about it.....it is market driven. Think about how many heatsink reviews you have seen, where the first thing they do is show you a picture of how much reflection there is from the base:hmm:

    But in the end......it all comes down to what you feel like doing. As I said in the guide....it is optional.
     
  2. mainman

    mainman Mr. Nobody

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    Anouther excelent guide...may be needing it soon....congrats buds this was really a great idea...keep up the good work...keep them comin.:)
     
  3. The_Neon_Cowboy

    The_Neon_Cowboy Well-Known Member

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    SLK 800U IS ONLY LIKE $30 SHIPPED
    ;)
     
  4. craig588

    craig588 Banned

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    these were temps taken from an average of 1 hour under load. (Speed fan automaticly calculates the avarages so it might have calculated it wrong, but I doubt that)

    even if it was affected by a room temp increase, that still means that lapping doesnt do much because if it was cooling better and the room temp increased it probably should have stayed the same.
     
  5. The_Neon_Cowboy

    The_Neon_Cowboy Well-Known Member

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    another 8 hourse and i'll have a good ref for ya
    i of couse have recently did some lapping of my own
     
  6. eyeguy616

    eyeguy616 ZZzzzzzzzzzz...........

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    OK, ok, when I bought my slk-800a it was $45. :rolleyes: The alx-800 goes for $20-$25 and does as good a job, so :p.

    Still, I wonder how good a silver (core or whole thing) heatsink would do.... Anyone have a pile of cash laying around to buy some silver to find out? Possibly get enough to weigh as much as an SLK-900/800.
    Let's see.... as of today the silver rate per ounce is ~$6.19 and the SLK-900 (for AMD) is 570 grams and 1 ounce = ~28 grams... so 570 gram = ~20 ounces which would be ~$124! :eek: :uhoh:

    ~eyeguy616
     
  7. Matth

    Matth Flash Banner Hater

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    I recall reading somewhere else that the only gain from a mirror finish is in appearance, and that it MAY perform slightly worse than satin.

    Suggestions were that a non-mirror finish provides a better thermal interface to the heatsink paste, through greater contact area, or that makes it easier for any excess paste (don't dollop it on!) to squeeze out.
     
  8. The_Neon_Cowboy

    The_Neon_Cowboy Well-Known Member

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    sliver is less thrmal conductive then copper, also it costs alot more


    the finish isn't the biggest factor the cpu 's surface being 101% flat is

    thats the whole point of lapping has only slightly to do with the surface it has mostly to do withit being absoluly flat

    [pople are useing power tools etc .. you cant you wont end up with a 101% perfectly flat perfectly smoothe surface


    i've had heasink pull the cpu out of the socket when trying to remove them becouse the connecting was so strong (useing as3)
     
    Last edited: Jan 9, 2004
  9. The_Neon_Cowboy

    The_Neon_Cowboy Well-Known Member

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    here a shot from the artical i was working on.... but roadee beat me 2 it :tears:

    [​IMG]
     
  10. PoopyTheJ

    PoopyTheJ New Member

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    Playing second fiddle is always rough. Of course you should have some practice trying to keep up with me in CoD. :D :p
     
  11. The_Neon_Cowboy

    The_Neon_Cowboy Well-Known Member

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    hey areun u that guy thats always on the ground in a pool of blood?
    with me pumping a fex extra rounds in lol
     
  12. Roadee

    Roadee Never forgotten

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    This is what was wrote in my article, "Polishing the surface is not required if you have used a fine enough grade of sand paper, but really makes your work look good."

    Everyone is going to have a different opinion about something, and you are going to see something a little different each place you go to. But does that make it "correct", just because you read something else.......somewhere else? Grooves in the surface TAKE AWAY contact area when collecting heat.......they add too when dissapating heat. In other words.....the smoother the surface......the more heat the metal collects.......the more fins on a heat sink.......the more surface area to dissipate heat.

    FACT

    Theramal compound is only used in order to aid the transfer of heat from the CPU to the heatsink. It is needed because of imperfections on the surface of a heatsink, as in, it fills in the scratches and pits. The fewer imperfections.....the less thermal compound is needed. With this in mind, lapping a heat sink ensures the surface is as close to perfectly flat as possible. Using finer and finer grades of sand paper makes more surface contact available, by removing imperfections on the surface.......as in scratches and pits.

    Rubbing compound and polishing compound are forms of abrasive's.......much like sand paper and used for the same intent. To remove material. Only there "grit" factor is more like 3000 to 10,000 grit. There sole purpose is to remove imperfections. In doing this the surface will get shiny in appearance. This shine is caused by light rays bouncing off of the surface. The less imperfections that exist, the more light will bounce off of the surface without interference. Thus giving you that "mirror" finish.

    The CPU's that are made do not have finely machined surfaces, so there is a need for thermal compound to aid the transfer of heat. Even if your heatsink is PERFECT........the CPU still isn't.

    How much time, if any, you spend lapping a heatsink is up to you. Whether you prefer to go the extra step to polish it is up to you. Even if you get the heatsink surface perfect, the cpu die will not be. Even if you were anal enough to lap the cpu, you may or may not gain a losely measured amount. ONLY scientific, calibrated measuring devices, that measure temperature to .0000000, and are done in a controlled environment, are going to give you accurate temperatures and differences in temperature due to lapping and polishing.

    Computer's are a hobby for many of us, how serious we are about the hobby is a personal choice, much like polishing a heatsink. Expand your horizon's whenever possible and remember to have FUN:D

    Roadee
     
  13. The_Neon_Cowboy

    The_Neon_Cowboy Well-Known Member

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    lol ...

    thats why some people lap thier cpu's
     
  14. Judas

    Judas Obvious Closet Brony Pony

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    you'd think that'd be a bad idea..... but.... i saw an article were someone lapped there abit NF7-S northbridge chip.... and they got a massive preformance increase do to it being alot more overclockable...
     
  15. Roadee

    Roadee Never forgotten

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    There is so many things you can do to increase your overclock.........just depends on how far you want to go. This article was just for a simple performance increase.
     
  16. Judas

    Judas Obvious Closet Brony Pony

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    ... i'm willing to buy a kyrotech case in about 5 years..... $2000 just for the hardware...... but damn.. compressed liquid nitrogen.... -198 or lower cpu temps... and those kind of temps on 4 other things.. such as vid.... north...south bridges.....maybe another cpu if your running dual....
     
  17. BWX

    BWX get out and ride

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    I just lapped my heatsink- it took about 6 hours- the surface was pretty big, and uneven. I started with 250 grit for about 2 hours, then went to 350 grit, then 600, then 600, then 1500, then 2000. I didn't polish it either, after 200 grit it's pretty shiny anyway.
     
  18. Roadee

    Roadee Never forgotten

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    If you can.........post a pic of it :D Also......is this the first one that you have done?
     
  19. BWX

    BWX get out and ride

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    My camera quit working, so I won't be able to post a pic any time soon :( -But it's about the fourth one I have done, including video card heat sinks. I used a piece of 3/4" mdf with a 1' x 1' mirror tile attached. I also used that 99% pure isopropyl alcohol you can get in a metal can from Home Depot. The lapped heatsink gave me allot better temps, but I was also using a 1.5v Tbred going from a Palamino, so I can't really compare the temps, but I'm sure it's a much more efficient cooler now.. I tried the way you were talking about, going back in forth in one direction as opposed to a circular motion like I used to do and it seemed to work just fine, plus I could use smaller pieces of sandpaper. I wish I did have a good camera to take some pics, the difference of the surface before and after is pretty amazing.
     
  20. Roadee

    Roadee Never forgotten

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    I think it is great that the sanding technique in the guide worked for you and that you were happy with the results. It made doing this article well worth it.;) I hope you consider doing an article of your own soon, as well as other member's of DH.
     

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