# Pure copper in CPU heatsinks?



## punkymunk (Oct 20, 2015)

New here and I hope I'm posting in the right topic forum. I punched out a solid copper core from a CPU heatsink that was surrounded by aluminum and was just curious if anyone knows if this is pure copper or more likely an alloy of some sort. I did try searching the forum and other sites on the web with no luck. The weight is 5.1 oz / 146g and measures 1-3/8" tall x 1" diameter (3.5 cm x 2.5 cm). Picture is attached of the copper. Thanks!


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## Anonymous (Oct 20, 2015)

Yep that's pure copper right there.


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## Geo (Oct 20, 2015)

Yes, Pure copper core.


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## punkymunk (Oct 20, 2015)

Cool... thanks! This will make for a cool paper weight either way but was just curious in case I ever decide to sell it lol


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## glorycloud (Oct 21, 2015)

I get heat sinks like this all the time and I just separate them from the ones that are only aluminum
and sell them to the local scrap yard. They pay a little more for them since they have copper in them.
They pay a whole lot more for copper though.

What method do you use to "punch out" the copper cores? 

Thanks!


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## Anonymous (Oct 21, 2015)

Glory you can push the central core out with a press mate. Or you can make your own press with a small circular peice of metal, support the edges of the heatsink and knock them out. They will only come out one way though because they are chamfered 8) 

Well worth the effort due to the uplift in the price for pure copper + pure aluminium vs the price for mixed metals.


Jon


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## solar_plasma (Oct 21, 2015)

I wonder what the solder is made of. Anyone who has examined it further?


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## silversaddle1 (Oct 21, 2015)

I have never seen on soldered in before. Not saying they don't. To remove these is real easy if you have a sawzall and a vice. Simply put the HS in the vice so you can cut between the fins down to the copper core. Once you make the cut, tap it with a hammer and it falls right out. Or, we have a 35 ton punch press that knocks them out pretty damn fast!


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## solar_plasma (Oct 21, 2015)

Only one time I took this kind made of alu and copper apart, lot of work, because it has been soldered. Since it is Rohs chances are, it contains a little silver.


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## g_axelsson (Oct 21, 2015)

Two transformers of the same size, side by side with a spacing that allows the core to drop down. Put a bolt with the head down in the hole and a few whacks with a small sledge hammer and it's out.

There are other types with a small copper disc pressed in and no hole through, same procedure but a narrow chisel goes straight through the aluminum and knocks the disk out.

Any soldered coolers usually have enough spacing so the copper core falls off if the heat sink is heated by a hot air gun.

Göran


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## glorycloud (Oct 21, 2015)

You guys are great!! Now I just need to carve out and hour or two to do all the work. 8)


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## punkymunk (Oct 22, 2015)

In my case of the above picture... there was no solder or over lapping type from the aluminum like in some other heatsinks. In this case just a good thick punch tool and a hand held sledge did the trick for me while positioned on top of my vice where the copper core could just fall out once done hammering. Took like 1 minute or so to hammer it out. If I happen to run across another intact I will upload a picture.


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## upcyclist (Nov 2, 2015)

punkymunk said:


> New here and I hope I'm posting in the right topic forum. I punched out a solid copper core from a CPU heatsink that was surrounded by aluminum and was just curious if anyone knows if this is pure copper or more likely an alloy of some sort. I did try searching the forum and other sites on the web with no luck. The weight is 5.1 oz / 146g and measures 1-3/8" tall x 1" diameter (3.5 cm x 2.5 cm).



Random nerd observation: Another clue as to whether or not your object is pure copper: see how close your object's density (8.46g/cm3 by your metric measurements) is to the density of copper (8.96g/cm3). Of course, how close is "close" depends on the accuracy of your measurements. You could also dunk it in a graduated cylinder to get the volume, or use a specific gravity scale.


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## rickbb (Nov 2, 2015)

spaceships said:


> They will only come out one way though because they are chamfered 8)



Something else I found out the hard way. After I've almost finished a box full I figured out why half of them were popping right out and the other half would not budge until I used a hack saw to split the Al apart.


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## Anonymous (Nov 2, 2015)

rickbb said:


> spaceships said:
> 
> 
> > They will only come out one way though because they are chamfered 8)
> ...



Hey you're man enough to admit it 8) 8) 

Sucks doesn't it? Heck I've made some absolutely howling mistakes in my journey too 8) 8)


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## darinventions (Dec 20, 2015)

Ill come right out an admit..i don't know much about melting copper. but i did melt two of these plugs three weeks ago an poured a bar that weighed 2.5 oz.s. there was a LOT of slag..don't know if it was impure or if i didn't melt it right...like i said I'm not to familiar with copper ..i guess the only thing that i can say i did right was. melting it in front of an exhaut fan


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