stoping copper heatsink from oxidising

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jhh
Posts: 218
Joined: Sun Jan 19, 2003 4:47 am

stoping copper heatsink from oxidising

Post by jhh » Wed Feb 05, 2003 5:18 pm

I live by the sea now, so metals oxidise a LOT quicker than inland, I don't know a figure but from experinace it's a lot worse than twice or three times as bad.

Which is bad news for my copper Zalman, after a few weeks it's already covered in a thin film. Anyone got any ideas what i can do about this? I know there's a gold-plated one, but that seems a bit overkill.

Gandalf
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Location: Belgium

Post by Gandalf » Thu Feb 06, 2003 12:56 pm

The oxydation is more than likely caused by high humidity .. so eliminating that would be a good start I think. There are devices (or frigging huge machines) for this ..

jhh
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Post by jhh » Thu Feb 06, 2003 2:45 pm

Humidity yes, but I'd say that it's more the large amounts of salt in the air, which acts as a catalyst. I live right on the very coast (ie I step out my door and I'm on the beach) Cars here rust much sooner than anywhere!

JarsOfFart
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Post by JarsOfFart » Sat Feb 08, 2003 6:47 pm

I'm not sure how viable this is, but you can chrome the heatsink. I remember reading somewhere that the plating prevents oxidation.

jhh
Posts: 218
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Post by jhh » Sat Feb 08, 2003 7:11 pm

unless you can do it in the pressure cooker I might find that a bit difficult.

Zalman sell gold plated versions already, seemingly not for performance boost (they list exactly the same max specs as plain copper) so I guess longevity.

If I was to plate it somthing black would prob give the best results, or should that be silver? I forget. Whatever colour it's no good unless I can do it without specuial equipment. I did once copper-plate somthing in science class, but then that seems a bit pointless here :?

JarsOfFart
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Post by JarsOfFart » Sat Feb 08, 2003 8:02 pm

The guy from Tweakmonster.com got some parts chromed for his Project Blue Sun. He sent them to some person.

cyanosis
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Post by cyanosis » Sun Feb 09, 2003 3:33 pm

If I remember my electrochemistry, you can attach a piece of Zinc or even Aluminum to the heatsink, and it should act as a sacrificial anode, corroding instead of the copper. Al should be fairly easy to obtain...

jhh
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Post by jhh » Sun Feb 09, 2003 3:46 pm

kewl 8) what exactly am I looking for? Is a just a piece of Alu foil ok? There's already an aluminium filter on the duct to the heatsink which doesn't seem to be too keen an sacrificing itself, any idea how should I attach it?

btw, platting seems like a no-go, too expensive!

cyanosis
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Post by cyanosis » Sun Feb 09, 2003 6:15 pm

I'm not sure how well this will work actually, having never tried it. You know, the whole theory vs. practice thing... but yeah, in theory, aluminum foil should work.

I'd buy some of that CLR crap they always advertise on tv, dunk the heatsink in it to remove the corrosion that's already there, then try the aluminum. If it still corrodes, then ignore me :) If it doesn't, you win.

cyanosis
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Post by cyanosis » Sun Feb 09, 2003 6:32 pm

Oh, and as for attaching it, just jam a bit of foil between the fins... the point is to make electrical contact...

jhh
Posts: 218
Joined: Sun Jan 19, 2003 4:47 am

Post by jhh » Sun Feb 09, 2003 6:45 pm

gotcha. at the very worst it'll just give the heat somthing else to be dispersed through - never a bad thing.

crisspy
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Location: Powell River, BC, Canada

Post by crisspy » Mon Feb 10, 2003 5:23 am

For cheap and better than plain copper, I suggest MG Chemicals Liquid Tin. It is used for coating home etched bare copper circuit boards, and it definitely helps against corrosion, albeit not as much as gold. You would want to get the metal very clean first though.

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