help determining metal type

[HaLo2FrEeEk]

A few months ago I found what I believe was an old uninterruptable power supply from 1994 (the year was printed on the inside of the case). Inside it was a lot of beautiful metal. Lots of copper, but also a heat sink which weighs a few pounds and is black. I'm not sure what type of metal it is, although I have a suspicion that it's probably anodized aluminum. It feels heavy for its size, but I can't imagine something that big being pure copper. Is there a way I can tell what it is? I don't have a scale so I can't weigh it.

[Rustjunkie]

The bottom of the heat sink should be flat so just scratch or sand that flat surface until you see bare metal and a copper insert will stand out, if it's pure aluminum or copper that should be fairly obvious once the anodizing is sanded or scraped away.

[HaLo2FrEeEk]

As I suspected, it is indeed anodized aluminum. I used a grind wheel on my dremel to scrape away a bit from a corner and found shiny silver color. Too bad, I wish it was copper, but still, it's a few pounds of aluminum.