Wayne, Wayne, Wayne,
You have been giving some good advice lately, but if want top billing you can't just wet the surface. You should have started this with "How to foil your solderability problems" and at the conclusion obviously stating "that's a wrap".
Dewey 

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
Sent: Tuesday, February 05, 2013 4:31 PM
To: [log in to unmask]
Subject: Re: [TN] Silver Sulfide & Plasma

Hi Rich-

Mildly oxidized ImAg usually solders fine, even if it doesn't look good.  So try a bit.  If you really need to do something, then I don't think a plasma will help.  There is only a very tiny amount of silver on the surface, so if you remove the ugly stuff, you'll most likely expose a bunch of copper.

So IF anything is needed, then the common approach is to REDUCE the silver oxides and sulfides back to elemental silver.  This is done the same way as advertised frequently on late night TV (only they use snake oil and do voodoo dances):

Heat some water up to 70C and add 1TBS/quart of baking soda.  Dissolve the baking soda.  Then take some new shiny aluminum foil and crumple it up, then iron it back out.  Put this in the hot water bath with the circuit board.  It doesn't have to actually make contact with the circuit board, and you really don't need a whole lot of aluminum foil.  Within about 2 minutes, the freshly exposed aluminum will pull the oxygen and sulfur away from the silver and you will be back close to the original finish.

Rinse THOROUGHLY in DI water, then dry the board in an oven until it is completely baked out.

Wayne Thayer

-----Original Message-----
From: TechNet [mailto:[log in to unmask]] On Behalf Of Richard Kraszewski
Sent: Tuesday, February 05, 2013 5:54 PM
To: [log in to unmask]
Subject: [TN] Silver Sulfide & Plasma

Any of you ever have luck cleaning silver sulphide off of a PCB enough to make it solderable with NC flux, by using plasma?

If so , can you please provide me with the gas mix you used?

Thanks

Rich  Kraszewski
PLEXUS


______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] ______________________________________________________________________

______________________________________________________________________
This email has been scanned by the Symantec Email Security.cloud service.
For more information please contact helpdesk at x2960 or [log in to unmask] 
______________________________________________________________________