pickling problems

[KarenfromN.O.]

Help!  My pickling solution keeps getting contaminated.  I am using copper tongs, mixing the Sparex with water according to the directions.  I've been placing silver items in the pickle post soldering and the last batch came out blackened with some rusted areas. 
How can I salvage the last batch of ruined silver?  Can I use the same pickle pot for argentium, fine and sterling silver?  Could it be the type of solder I am using?  Could the culprit be a chain (which said 'sterling') that may have had some non-silver parts to it?
This is not the first problem I've had -- my pickle never seems to be clear, always murky.   I've purchased a new pot, and still the same problems.
I'd appreciate any suggestions.  Pickling shouldn't be this difficult!

[Polly]

Hi Karen,

It sounds to me like you're doing the right thing. What type of solder are you using? 

And, it's possible the sterling chain is rhodium plated to prevent tarnish.  I don't think any of our sterling chain is rhodium plated.  However, sterling chains sold at/for the gold-and-diamond types of jewelry stores are frequently rhodium plated. I'm not sure what type of effect that would have.

I think Kurt (aka MetalMan) will weigh in soon on your questions.

--Polly

[Russ Nobbs]

"blackened with some rusted areas" is not a common issue.
When you say "rust" do you mean reddish rust like on iron or steel objects?
Will a magnet pick up your work? In other words is there some iron involved. There should be no iron or steel in your ceramic pickle pot.

Yes, a separate pickle pot for Argentium is a good idea. See the fact sheet Rio provides on Argentium at http://www.yourriogrande.com/downloads/applications/DocumentLibraryManager/upload/ArgentiumSterlingSilver.pdf In that pdf Cynthia says

"In my studio, I use one pickle pot for all metals—silver,
copper and gold—and have had no trouble (yet!). It
certainly would be a good idea, however, to avoid any
cross-contamination with other alloys by having a separate
pickle pot for Argentium® Sterling Silver. I recommend
a separate pickle pot if you work a lot with copper alloys,
or are in a group studio situation, or simply like to be
cautious.Note that the reason for being concerned about
contamination is the effect that copper deposited on the
surface of the silver could have on tarnish-resistance."

In my experience soldering and pickling,  the problem I most often encountered was plating some copper onto the silver because the pot was contaminated from GF, copper or brass. I left a chunk of silver sprue in the pot to attract any copper. We'll ask Kurt (Metalman) to look at your questions and see if he has any suggestions.

[Metalman]

Apologies for being a little late to jump in.
First thought is to ask what you water source is. Silver items getting black in the pickle is very odd. Potentially well water with highish iron or sulfur could have a negative effect.
Any iron or steel at all in the pickle is problematic - although - my understanding is that the iron causes an electrolytic event when there is a build up of copper that causes copper to plate out onto your silver items. This will not happen in fresh pickle since there isn't the copper ion build up - needs to be old used pickle. 
How old is your pickle batch?
any contamination possibilities?
Rust?  hmmmm.... is it rust or some kind of orange spotting that looks like rust?
What flux are you using? - Is the flux being completely removed in the pickle?   
Are you , or do you heat your flux? this can be a real benefit

Not many suggestions - but lots of questions - my apologies - there are so many variables
let us know - will keep an eye out for your posts
KM
The Metalman

[KarenfromN.O.]

Thanks to everyone for your suggestions.  I think Polly hit one potential source of contamination -- I did thrown silver chains in the pickle to clean them and the first sign of trouble was that the clasps turned black.  No more department store bought chains in the pickle pot. 

There is a reddish buildup on just 3 identical  "silver" beads I purchased on EBay.  Perhaps they are not sterling silver?  The good news is that now dry, the reddish material brushes off.  Would it be OK to tumble everything to clean it?

I will use a separate pot for Argentium, it seems to react differently to the pickle than the sterling.

[Russ Nobbs]

Yes, tumbling should do it.

Just remember to avoid the mistake most of us have made at least once!
If the beads have large enough holes to allow the tumbling media or shot to get in, be sure to string them on a large enough wire that the media can't get inside the beads.

Cleaning silver chain is better done with a polishing cloth or one of the silver dips. Rinse really well in clear water if you use the dip.