Re: [ATM] Mirror Silvering

["James Lerch" <jlerch1@tampabay.rr.com>]

----- Original Message ----- 
From: "Mark Holm" <mdholm@telerama.com>

> They opened the safe, wheeled the cart of
> silver ingots to the reactor and pitched them in, causing the acid to
> bubble fiercely, giving off hydrogen, and the silver metal to dissolve
> away.

** Danger **

The reaction of Nitric acid with Silver metal actually evolves Nitrogen Dioxide 
gas, really nasty stuff.  Here's a quote from the Merck Index (#6698, Vol.12)

"Deadly Poison ... One of the most insidious gases.  Inflammation of
 the lungs may cause only slight pain or pass unnoticed, but the
 resulting edema several days later may cause death.  100 ppm is
 dangerous for even a short exposure, and 200 ppm may be fatal."

I only toss out the "danger" comment, as I don't want someone reading the 
article some time in the future to accidentally think production of Silver 
Nitrate is that simple.  Well, OK, production of Silver Nitrate really is that 
simple, but the nifty golden brown gas that is evolved can, and if given an 
opportunity, WILL kill you!!

Here's what the reaction looks like:

Ag + HNO3 --> AgNO3 + NO + H20

2NO + 02 --> 2NO2 <--> N2O4

Here's an interesting read from Wikipedia:
http://en.wikipedia.org/wiki/Nitrogen_dioxide

Now, with all that being said, I'm not one of those "Chemistry Alarmist" types. 
I have to admit, back in my mirror silvering days I manufactured more Silver 
Nitrate than you could shake a glass stir stick at.  So much in fact, I was on a 
first name basis with the local jewelry shop where I purchased 1oz silver 
bullion coins by the six pack.

The good news is, not once did the Nitrogen Dioxide gas kill me, but I was 
certain it wanted to, and I knew this in advance. Your mileage may vary.....

Take Care,
James Lerch
http://lerch.no-ip.com/atm (My telescope construction,testing, and coating site)
http://lerch.no-ip.com/ChangFa_Gen (My 15KW generator project)

"Anything that can happen, will happen" -Stephen Pollock from:
"Particle Physics for Non-Physicists: A Tour of the Microcosmos"

" Press on: nothing in the world can take the place of perseverance.
Talent will not; nothing is more common than unsuccessful men with talent.
Genius will not; unrewarded genius is almost a proverb.
Education will not; the world is full of educated derelicts.
Persistence and determination alone are omnipotent. "
                                                           Calvin Coolidge





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