"jw" wrote in message
ups.com...
I have noticed recently that any exposed copper in my shop has a black,
burnt look to it.

What is causing this? I first noticed it in my electrical panel, and
thought I must have really overheated that circuit. Then I noticed it
on the exposed ends of some scrap wiring I had around, so I concluded
that wasnt' the case.

I know exactly what it is, but not necessarily where it's coming from.

The culprit is H2S - hydrogen sulfide gas. The source???? Who knows. You
do.

Are you on a private well for water? Do you have sulfur water? In or even
NEAR your shop will suffice.
Do you work with highly sulfured oil in a small shop? That'll do it. (*but
not unless you're actually cutting with - heating - it)
Do you have anything proteinous rotting around there (lotta shops have a
dead rat in the wall) ? That'll do it.
How-bout black powder arms and/or powder stored in your shop? *that's a bad
source of it*
Have you had a spill of, say, a gun bluing fluid in there?
Gas leaks? (some H2S in natural gas). Leaking mixed-gas (LP is sometimes
not propane, but a mix of propane, butane, and natural gas with its H2S
component.)

HCl fumes (hydrogen chloride) can do it more slowly. Have you been
machining lots of PVC? That'll do it.

A few ideas.
LLoyd