"Andrew Mawson" wrote in message
...

"Ivan Vegvary" wrote in message
news:mLkNi.6808$PV1.523@trndny08...
Just took off the aluminum siding on the front of my house. I don't
know if
it's worth the gasoline to drive it to the scrap metal dealer. I
probably
have about 20 lbs.

Is this siding aluminum suitable for melting and casting?

Another question. My wife has three kilns. They go up to about
2000° F.
Can I just simply snip up a bunch of siding, place it in a cast iron
skillet
and put it in one of her kilns? Just wondering.

Ivan Vegvary



You are fighting physics. The ratio of surface area to volume of your
siding is far too high and as you melt it, it will form a very large
proportion of various aluminium oxides which will settle out as a
thick layer of dross on the surface of your melt. Melting it
commercially they would plunge it into an already molten pool of
aluminium so as to exclude the air. I found all this out when I
started casting a couple of decades ago and was re-cycling beer cans.
Produced as much dross as aluminium.

Now if you cut your siding into kiln sized pieces in a skillet, and
filled the kiln with an inert gas you'd be fine !

AWEM


Pretty much what Andrew said, although I'd add that the vessel in which
you'd do the melting wouldn't be a good choice. Molten metals have
considerable solvent power------and will dissolve other metals when well
below their melting points. That principle is used in assaying, where
molten lead, reduced from litharge, collects metals that melt at much higher
temperatures (platinum, for example) and includes them in the button.
Platinum melts well over 3,000 degrees F, yet it is dissolved nicely by the
lead at a much lower temperature.

If your objective were to reduce the aluminum for the sake of the exercise,
a cast iron skillet would work, but you'd be contaminating the aluminum and
altering its characteristics. You would end up with aluminum that is of
poor quality. You'd also likely regret the stink and smoke that came from
the finish on the siding.

Extruded aluminum, or rolled aluminum doesn't cast as well as aluminum
alloyed for the purpose. If your objective is to use the resulting metal
for casting, you'd be far better served to re-melt existing castings, which
are alloyed appropriately and flow much better.

Right now, the scrap market is quite strong. If you have a recycling yard
near, you might be pleasantly surprised to find your material is worth the
trip. It's no retirement plan, but it should buy a nice lunch for you and
the Mrs.

Harold