Die cast aluminum often has a very high amount of zinc, which is used to
make the aluminum flow better when casting, but once alloyed with the
aluminum it not only weighs more, but must be separated before the aluminum
can be used on its own. Die cast aluminum with zinc must never be used in a
wet environment because of electrolosis and unfortunately it is all the
time.
Steve

"TwoGuns" wrote in message
...
Last month I bought about 50 damaged computer hard drives from a local
computer repair shop. I salvaged the magnets, motors and assorted
bearings, nuts and screws. The cases and circuit boards were loaded up
to take to a local metal recycler. I had called them before the trip
for a price check. They were paying $.68 for Aluminum unless it was
die cast. If it was die cast Aluminum the price was only $.34. Of
course when I get there they say it was all die cast. It was too
damned hot & humid to argue and I sure as hell didn't feel like taking
the junk back to the shop so I let them take it. Just for future
reference what is the difference between die cast Aluminum and the
higher grade and how can I tell? I had hit the tops of several cases
with a grinding wheel and if it showed shiny and bright I figured it
was a higher grade. What I assumed was die cast had a dull finish when
hit with a grinder. I know they are full of **** at the recycler but I
didn't have enough information to make my case.

I was surprised at the price they paid for old circuit boards ($2.40/
pound but it takes a lot of circuit boards to make a pound of them. I
do have a nice assortment of small bolts & screws though. One of them
was a perfect fit in a pair of old eyeglass frames I have on hand.

DL