Prodigal Stranger...nice to hear, because in my former life (am retired
today) some saw me as the Profitable Strangler ...
On 6 February 2013 16:20, Stadem, Richard D. <[log in to unmask]>wrote:
> Totally understand, Dewey. That Pauls needs to be Led Through the Garden
> Fence. But be careful of overcorrection with that old salty dog Doug, it
> could lead to Lime Street Blues. But yes, immersion silver continues to
> Shine On Brightly, especially here at Home. It is Truly Something Magic.
> But Doug and I are Poles Apart when looking for Signs of Life on the
> Southampton Dock. Indeed, Those Were the Happiest Days of Our Lives.
> And, Inge, it sure is good to be hearing from you again. Welcome back,
> Prodigal Stranger.
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Whittaker, Dewey
> (EHCOE)
> Sent: Wednesday, February 06, 2013 8:37 AM
> To: [log in to unmask]
> Subject: Re: [TN] Silver Sulfide & Plasma
>
> Richard,
> You're welcome, but this was also a follow-up to my comments to Wayne.
> Your reference to a darker shade of pale (Procul Harem - A Whiter Shade of
> Pale) led me to the use of an old term of endearment Salty Dog (another
> album by Procul Harem). I knew you knew that, but I have to explain to Doug
> a lot. Also, before Bev and others point out I incorrectly used led, it was
> in tribute the bands similarities to Led Zeppelin (think last week and
> hydrogen).
> Dewey
>
> -----Original Message-----
> From: Stadem, Richard D. [mailto:[log in to unmask]]
> Sent: Wednesday, February 06, 2013 7:22 AM
> To: Whittaker, Dewey (EHCOE); TechNet E-Mail Forum
> Subject: RE: Silver Sulfide & Plasma
>
> Thanks, Dewey. Every old dog has his day in the sun once in a while.
>
> -----Original Message-----
> From: Whittaker, Dewey (EHCOE) [mailto:[log in to unmask]]
> Sent: Wednesday, February 06, 2013 8:07 AM
> To: TechNet E-Mail Forum; Stadem, Richard D.
> Subject: RE: Silver Sulfide & Plasma
>
> You salty dog! Good job.
> Dewey
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Stadem, Richard D.
> Sent: Wednesday, February 06, 2013 6:54 AM
> To: [log in to unmask]
> Subject: Re: [TN] Silver Sulfide & Plasma
>
> Hi, Rich
> If you have mildly tarnished IAg-finished PWBs, I recommend you print
> paste on part of one of the PWBs or a complete solder sample coupon and
> send it through the reflow as a solderability test. They will usually
> solder out to the edges of the pads just fine. You can then wick off any
> solder and still use it as a production PWB.
>
> Wayne is correct. Plasma will take the finish right off.
>
> If there are solderability issues, go back to the PWB vendor. There are
> processes where they can strip off the IAg finish and re-plate the IAg, and
> I have done this two or three times with no issues. If the PWB supplier
> does not have this capability, there are others who can do this for you,
> even if they did not fabricate the PWBs in the first place. Typically the
> PWB supplier outsources this type of plating, and they can tell you who can
> re-plate it for you.
> I have used IAg PWBs that sat around in a warehouse for 5 years in a
> previous life, completely exposed to the elements, and had turned a darker
> shade of pale, so to speak. But they soldered up with a better DPMO than
> the ones less than 6 months old!
> dean
>
> -----Original Message-----
> From: TechNet [mailto:[log in to unmask]] On Behalf Of Wayne Thayer
> Sent: Tuesday, February 05, 2013 5:31 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
>
>
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