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Got two heatsinks that I pulled the copper out of already but I'm left with fairly heavy fins that bend like aluminum, are slightly pulled toward a neodymium magnet and the exposed metal after breaking is white.

Thoughts on what it is made of?

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My grades are my own opinion and not an official grade from Boardsort

For what it's worth, there is solder still on it, though I keep going back and forth in my mind as to whether there could possibly be enough to make them feel as heavy as they do.

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Here to learn more so I can recycle more
My grades are my own opinion and not an official grade from Boardsort

those kind of heat sinks are not always aluminum. I melted a few down and they don't cast like aluminum or melt at the same temp.

I bet it some sort of alloy or stainless. try taking a grinder to it to see if it sparks? If it sparks its likely stainless of some sort. But my money is on a alloy of sorts.

Short a grinder for spark testing, I can't imagine stainless would bend as easily as this did and it only took a couple bends to break

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Here to learn more so I can recycle more
My grades are my own opinion and not an official grade from Boardsort

you'd be surprised given how thin it is. but my money is on a alloy if some sorts. however i always toss those types of heat sinks in my aluminum pile

My suggestion is to cut or pull a tiny piece from the fins.
Then test the piece alone with the magnet.


Aluminium sinks are rarely 100% clean.
Usually there’s some nickel content. And if it’s over 1-3% it will pull.
I just had an argument over a bracelet at a trusted buyer this week when it stuck to the magnet: sure I was wrong till I put $20 on the line. Test it with the xrf scanner. Said if I’m wrong I’ll pay you $20 (their non-customer scan test price) and if I’m right you pay me $50 for the $$30 bracelet
My 925 silver bracelet was 075 nickel.


The fastest test for low cost is a grinder spark test.

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42 6F 61 72 64 73 6F 72 74 2E 63 6F 6D

Nickel seems to get into everything now. Ive had aluminum brass and even copper give a slight pull to a hard drive magnet. Some brass was actually giving a fairly strong pull but we cut it up and ground on it. Nothing but brass but must of had a lot of nickel in it!

Exactly what I did.


I can't remember now the why behind it but brass can become magnetic in certain applications.

I'll see if I can remember to take a piece home to grind.

_________________
Here to learn more so I can recycle more
My grades are my own opinion and not an official grade from Boardsort

I can't remember now the why behind it but brass can become magnetic in certain applications.
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Some brass/bronze alloys has iron in it too. My money is on a nickle alloy aluminum too.