Green patina questions

Ok, so it has been a very long time since I have tried patina-ing
anything... not since I was in college. Now, I am making a luna moth,
and I have it all together. I used argentium for the body, sterling
wire for the veins, a brass band on the body and copper for the
wings. I dug out my Tim McCreight Complete Metalsmith for the recipe
and info... and I do not feel it is complete. I have a couple of
questions...
1st, will either of the silvers patina, if exposed to the chemicals?
I do not want them to react, and I would put a resist on them, if
there is a potential that they will turn green, too.
2nd, where do I get ammonium chloride (sal ammonia)? The hardware
store? In college, I only remember making the recipe for blue and our
green patina was a bucket in the corner full of saw dust and urine
samples... I really want to try the Tim McCreight recipe instead.

Thanks to anyone who can answer my questions!
Melissa

On Wed, 02 May 2007 04:26:51 +0000, wrote:

2nd, where do I get ammonium chloride (sal ammonia)? The hardware
store?

Chemical supply houses in most cities will likely have it.
Also, p. 368 in Rio's tools catalog has a collection of pre-mixed patinas.

wrote:

1st, will either of the silvers patina, if exposed to the chemicals?

They'll probably get altered, so I'd either protect them with something
removable like wax, or plan on cleaning them up after with a flex shaft
buff.Silver probably won't be green. Ultimately, though, you just have
to do some tests before you go with the artwork. On all the metals.
That's really important.


In college, I only remember making the recipe for blue and our
green patina was a bucket in the corner full of saw dust and urine
samples... I really want to try the Tim McCreight recipe instead.

Actually you can do a pretty good job with salt and ammonia, which are
found in urine. But you can go directly with just those two household
ingredients. I did some dragonfly wings and they came out beautifully.

The trick is in the application, or non application. Traditionally, the
piece was put in some substance like sawdust. Better yet, 1) dip the
pieces in salt water and then 2) get some plastic mesh and suspend the
wet pieces over a container of ammoonia so the fumes will react with the
wet surfaces. Have the ammonia container and artwork inside another
container so you can confine the fumes. This is a bit more control-able
than using sawdust or wood chips or something like that. If you want sal
ammoniac, try Google and if you don't get a source, I will check some
old files. Also, I've read that there are salt and vinegar potato chips,
and if you put the wet piece of artwork......

Green patina questions
The great greens you get in these recipes come from various copper
compounds formed when ammonia and various ionic compounds - generally
salts interact with copper and each other. They will give little if
any green to silver, especially Argentium where some of the alloying
copper has been replaced with Germanium (Germanium forms a transparent
oxide layer very easily which acts as a protective layer preventing
chemicals from tarnishing the silver).

Ammonium chloride is also available from stained glass dealers where
blocks of it are used to clean soldering irons.

Good luck
Marlin