How do you clean severely oxidized heatsinks/coolers without affecting it's performance?

[DatGameh]

Some time in the future, I plan to do an experiment. It involves the use of a good heatsink.
I found an old AMD heatsink from about 7-10 years ago for about $7.40 dollars, but haven't bought it yet.
The AMD heatsink is physically in good shape, but it was poorly stored. This can affect the results of my experiment.

Using stuff like Brasso is definitely out of the question. It will leave residues.
There isn't one website that mentions the best way to remove the layer.
Some say that using lime works, while others say using vinegar is better.

Does anyone know?

 

[COLGeek]

Other than making sure that the mating surface (where the CPU and heatsink attach) is clean, I don't think you'll see an appreciable difference in cooling performance by the exterior oxidized surfaces.

The fan may be questionable though.

 

[Sarth67]

http://www.instructables.com/id/Electrolytic-Rust-Removal-aka-Magic/

 

[DatGameh]

Other than making sure that the mating surface (where the CPU and heatsink attach) is clean, I don't think you'll see an appreciable difference in cooling performance by the exterior oxidized surfaces.

The fan may be questionable though.

Although the areas where the aluminium and copper contact might not be oxidized, although less visible, I am very sure that the aluminium fins are covered thick in aluminium oxide. That will be the most problematic factor in terms of cooling efficiency.

 

[DatGameh]

http://www.instructables.com/id/Electrolytic-Rust-Removal-aka-Magic/

Sorry... This seems to be a little too difficult for what I'm going to do for a short while.

 

[Solandri]

Although the areas where the aluminium and copper contact might not be oxidized, although less visible, I am very sure that the aluminium fins are covered thick in aluminium oxide. That will be the most problematic factor in terms of cooling efficiency.

Aluminum oxide is not like rust. It's a very hard, interlocking crystalline material called corundum - aka rubies and sapphires. It's airtight so it forms a layer only a few atoms thick. The layer then blocks atmospheric oxygen from contacting the aluminum, preventing the creation of more aluminum oxide. That's why your aluminum foil sheets are able to stay nice and shiny. It's also why aluminum coatings are the preferred choice for front-surface mirrors (e.g. telescope optics) even though its reflectance is less than other materials like silver. It will stay shiny, unlike silver which will oxidize and tarnish.

If the fins aren't shiny like fresh aluminum, either they're dirty, or they're not aluminum.

(Totally different story in water. The aluminum oxide simply floats away, allowing the aluminum to continue oxidizing. This is what killed the idea the airlines tried of not painting their shiny aluminum airplanes to save weight. It worked fine in dry weather. But when it rained and the aluminum got wet, it began to corrode.)

 

[DatGameh]

Although the areas where the aluminium and copper contact might not be oxidized, although less visible, I am very sure that the aluminium fins are covered thick in aluminium oxide. That will be the most problematic factor in terms of cooling efficiency.

Aluminum oxide is not like rust. It's a very hard, interlocking crystalline material called corundum - aka rubies and sapphires. It's airtight so it forms a layer only a few atoms thick. The layer then blocks atmospheric oxygen from contacting the aluminum, preventing the creation of more aluminum oxide. That's why your aluminum foil sheets are able to stay nice and shiny. It's also why aluminum coatings are the preferred choice for front-surface mirrors (i.e. telescope optics) even though its reflectance is less than other materials like silver. It will stay shiny, unlike silver which will oxidize and tarnish.

(Totally different story in water. The aluminum oxide simply floats away, allowing the aluminum to continue oxidizing.)

If the fins aren't shiny like fresh aluminum, either they're dirty, or they're not aluminum.

Hmm... So it will only deviate it's performance by about 0.5% with the aluminium oxide coating?
Alright then.
By the way, I just looked a bit more carefully in the heatsink: There seems to be a gap between the heatpipe and aluminium fins. Could this area be subject to a layer of copper oxide? Since this is a more critical area, I might want to clean these areas specifically with some form of chemical, maybe.

 

[COLGeek]

CLR the metal parts and then rinse and dry thoroughly?

http://www.jelmar.com/CLRbasic.htm