[Audio Empire]

On Wed, 20 Jul 2011 18:35:31 -0700, Dick Pierce wrote
(in article ):

Audio Empire wrote:
The radio shack speaker cable was standard copper AFAICS,
Copper doesn't rust, but it does corrode

Actually, to be precise, the chemical process that causes
iron to rust is the same that causes copper to turn green:
the rersult is, in both cases, an oxide of the metal that's
formed the same way. Both are covered under the broad
blanket of "corrosion," of which oxidization by atmospheric
oxygen is but one type. Yes, copper doesn't "rust" because
the oxides of sopper doen't look the same as the oxides of
iron ("rust" being derived from one or another word for
"red").

Yes, I think we all know that. Only iron rusts. other metals corrode, but it
is all oxidation.

But, it's not that iron "rusts" and copper "corrodes" as
distinctly different processes: they're the same process
but with different names.

I see we have a a champion of the obvious in our midst. 8^)

Then we have the case of wire turning green inside an
insulating jacket: it's still the same oxidization
reaction, but one that is, ahem, encouraged by a less-
that-ideal choice of plasticizers in the insulation.

Certainly possible and I have seen the phenomenon,

Generally, plasticizers (the chemical that make plastic [n]
plastic [adj]) are pretty nasty. Dioctyl pthalate is one
that springs to mind and, hopefully springs right out again
quickly. A lot of these things are either sufficiently
volatile (meaning high enough vapor pressure) or unstable
under the unfluence of UV or ozone that the disappear,
the result being the plastic [n] is no longer plastice [adj]:
it gets brittle and crumbly, e.e., plastic that ain't so
plastic any more.

Like British car wiring from the late '50's and '60's

Quiz on Friday.

Looking forward to it.