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?
"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 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
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.
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.
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.