Discolored copper

ammonia? chlorine?

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

Sulphur, maybe.

Best regards, Spehro Pefhany

Excessive flatulance?

Don't laff. I had a student job in a place where special purpose CRTs were being made. The gun assemblies were mini-spot welded together in a small clean room. They traced poor performance of the cathodes in some CRTs to one assembler who pharted a lot when working there alone. The H2S he emitted poisoned the surfaces of the cathodes.

I also remember hearing that certain employees at watch factories got reputations as "rusters" because their skin moisture was much more corrosive than average, and somewhat similar tales about women assemblers who were ok in that regard save for a short period once each month.

Jeff

I also wanted to suggest farting, but thought that it would be too much after recommending a fart driven internal combustion engine recently.

As for corrosive skin, my own fingers used to have this effect: steel objects would rust where my fingerprints were, right on the fingerprint line.

I have a shooting friend that only owns stainless steel weapons for that same reason. Whenever he comes over, after handling a blued steel firearm, I make a habit of wiping it down with solvent/lube because he will leave rust spots behind.

Gunner

"Pax Americana is a philosophy. Hardly an empire. Making sure other people play nice and dont kill each other (and us) off in job lots is hardly empire building, particularly when you give them self determination under "play nice" rules.

Think of it as having your older brother knock the shit out of you for torturing the cat." Gunner

Ah ha. Probably a result of the overcharged battery a while back. !@$@%#$ timer stuck on the edge of off. I usually go check to make sure, one time I didn't......

Every time since then it has also shut off properly on it' own.

I knew it was some sort of chemical reaction, but chemistry wasn't(isn't) one my strong suits.

Thanks guys.

JW

Yep. I was leaving "rust fingerprints" on all metal things...

Might make for a bizarre external combustion engine though.

I attended the last New England Model Engineering Society's show and amidst the ubiquitous steam and Sterling engine models I found an engine type I'd never heard about before.

It looked like just another single cylinder horizontal steam engine, but there was a hole in the middle of the head which was valved by a pivoting shutter blade timed off the crankshaft.

A small alcohol burner was positioned so that its flame was adjacent to that valve. The valve pivoted open when the piston was moving away from TDC, sucking hot gases into the cylinder.

The valve closed near BDC and the gases cooled and developed a negative pressure so the atmospheric pressure on the back of the piston pushed it back towards TDC.

It was spinning away like mad, and the proud builder described it as an "atmospheric" engine. The only atmospheric engines I'd heard about before used condensing steam in a similar fashion, but seeing one running by sucking flame directly into the cylinder like that was a gas.

Jeff

quite amazing.

Oh! ,damn. I spent $30/gallon and another $50 for HASMAT fees for some liquid that does just that. ;-)

Larry

Too much farting?

Ni-SCNR-ck

You call this engine-type "flame licker". We call it "flame eater". A more sophisticated name is "vacuum engine". Yes, they run very fast, but have no power at all. Their overall efficency is about 0,5%.

Nick

Is it an OZONE issue or Sulfur issue. Are there currents in effect across the surface or do you live near a body of water or swamp ?

Martin

BTW... when I said that "HCl" can do it, too, I should have noted that chloride corrosion on copper can vary in color from a dark earthen brown to blue. But the black layer you saw is almost certainly from H2S.

LLoyd

Some of it, does have a bluish tint to it as well.

In either case, it seems that it can be linked to the overcharged battery.

I assume that this is not a "real" problem? Any existing wiring should not have developed extra resistance at the contact points. Any new stuff, will of course get cleaned(if needed).

Thanks

JW

Well, yes, and no. IF your connections were all perfectly tight, then the interface area will be "gas tight", and no corrosion should have intruded (at least very far) into the connections. If you suspect any of them were the least bit under-torqued, you better check them, and clean any suspect areas.

I had the same thing happen. My son turned my automatic charger to "manual" because, "it wasn't charging fast enough, Dad!" Needless to say, it boiled the battery dry before I discovered it. And yes, it corroded everything in the room.

LLoyd

I had a sheet of copper laying on the bench, and suffering from FFS (first flat surface) tendancies on some occassion, it had stuff laying on top of it. You can now see a perfect outline of everything that was on top of it. Doubting those contacts were "gas tight", I suspect I am ok.

But, to be "better safe than sorry" I will make it a high priority to check and retorque all of my electrical connections.

Thanks

JW