Does the copper base and copper heatpipes of heatsinks rust or oxidise?

Does the inner part of the heatpipes rust?

After clearing my store i found 1 long unused heatsink with copper base and heatpipes. The base surface looks pale but still looks copper to me. I suspect some mild rust. What can i do to remove the rust?

How about rusts inside the heatpipes?

Unrelated to copper:
Does the liquid in heatpipes dries up?

How do i find out whether the heatsink is still working or not?
17 answers Last reply
More about copper
  1. Rust is iron oxide, no, copper doesn't rust. It oxidises slower than iron, but it does tarnish. Metal polish will restore it to original condition. The heat pipes are sealed, so will not dry up.

  2. Does copper oxide affect the cooling ability of the heatsink? I intend to lap the base surface. Is it a wise choice? Will it oxidise faster?

    I don't know anything about polishing metal.
  3. Jelloz Dude :)

    "Polishing" metals (iron, copper, aluminium, etc.) is quite simple ... get a can of Brasso Brasso metal polish and an old cotton tee shirt, read instructions on can, shake Brasso well and have at it. With enough (easy) work the HSF base will become mirror-like :D Also, remember when mounting to CPU to use as little heatsink compound as possible ... a tiny dab smeared with finger tip EVENLY across CPU is ALL that's needed :D
  4. Copper oxide will adversely affect the cooling ability of the heatsink.

    Lapping the surface will not cause the copper to oxidise faster.

    Lapping should not be necessary is the surface is flat. Simply cleaning or polishing the surface should suffice (as mentioned by previous posters).

    However, if using polish, remember to clean the surface before mounting (polish will leave a residue). Arcticlean solution #2 or 90%+ isopropyl alcohol is generally recommended to remove any residues.
  5. Okay will try. Not very sure i will be able to get that certain Brasso brand. Will any metal polish work?

    So the oxides will get removed but will not affect the heatsink base?
  6. Quote:
    a tiny dab smeared with finger tip EVENLY across CPU is ALL that's needed :D

    Good method, but remember to put that finger tip in a plastic glove/bag beforehand. You don't want any impurities from your finger between the contact surfaces :)
  7. Yes - any metal polish should be fine.

    It won't affect the heatsink base as long as you thoroughly clean it afterwards to remove any residue. The oxidised layer is extremely thin (we're talking microns).
  8. What about the surface of the heatpipes? They look pale like the base.

    Does aluminum oxides then?
  9. The only surface I would worry about removing the oxide layer from is the face that mates to the CPU.

    In the world of heat transfer, the oxide layer of copper is somewhat less for conduction (CPU surface) and minimal effect for radiant heat (Fins and tubs), So this tells me to remove the oxide layer from the die surface. As for the heat tubes and fins, I personally would not.

    Copper will be oxidized in a few days (even if not readily apparent) after you clean it, so cleaning the oxide layer from the tubes is an ongoing process till you wear them away.

    The inside of the tubes should not have any exposure to oxygen and so will not oxidize.
  10. Thanks olgraybeard for the infos.

    If i use the heatsink would i need to check the heatsink base to check for oxides? Because if i use it there would be no air present as there will only be the thermal paste.
  11. Once installed, no air, no oxide, no worry.

    Most new heat sinks have a cover on them to be removed before installing that prevent oxidation. Again, the concept, no Oxygen, no oxide no problem. Does not hurt to look before installing.
  12. Okay i get it now...the heatsink originally came with the sticker but i kept it and have not used it for sometime.
  13. Every metal can be oxidised. It's just a matter of what conditions you use... (Look up a Red/Ox table for more info)
  14. Cooper corrodes as well and it forms a greenish layer which proctects the surface from further corrosion. However if this is located in contact areas like the base surface and radiator fins then it will insulate heat transfer. So it is best to remove it. You can use a fine sandpaper to safely remove the corrosion and polish the surface again. The liquid inside the heatpipe is either Acetone or similar chemical this boils at low temperature and carries the heat out to the radiator area and then gets dissipated by cool air. If the heatpipe has leaks then it is possible it could dried up and will affect it's cooling performance. You can test it by installing it to the cpu and they way you'll know by monitor the cpu temperatures.

    P.S. All forms of metal do corrodes, it's just a matter of time and exposure.
  15. Will the liquid dry out if there is no leak? Because the heatpipes gets heated on cools down often.

    How high temperature can a heatsink endure?
  16. If there's no leak or hole the liquid should not dry out. If there's now liquid in the heatpipes then the only explanation is that it leaks out and that the heatpipe has a hole or bad seal. Liquid do not sip through copper as copper is not phorous.

    As far as temperature, I'm sure it can able to withstand higher temps than the cpu chip can.

    The best way for you is to clean the cooler and test it to see if it still works.
  17. As long as you polish it and use some thermal compound, it will work fine.
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