Depends!
I know much more qualified individuals than myself will provide a complete
explanation.
The shelf life is completely dependant on the finish and how well that
finish was applied.
My experience with white tin (Omikron) was about a three month shelf life.
This is much shorter than the manufacturer of the process (Florida Certec)
specifies. They helped me trouble shoot the problem to improper plating
thickness. That PCB vendor is off our approved list and we no longer spec
white tin, we have a low PCB inventory turn over so it is the wrong plating
*for us*.
I have HASL PCB's that have been in inventory since before dirt was invented
and they still solder fine.
I think there is a comparison in the archives somewhere that tabulates the
different finish types and their respective properties. Probably worth doing
a search.
FWIT My .02$,
Dan
----- Original Message -----
From: "Bissonnette, Jean-Francois" <[log in to unmask]>
To: <[log in to unmask]>
Sent: Wednesday, January 29, 2003 12:54 PM
Subject: [TN] Shelf life of PWB


> What is the shelf live of a PWB.  After how long can I expect to have
> solderability problem?
>
> Thanks!
>
> Jean-François Bissonnette
> Vérificateur, Contrôle de la Qualité
> Électronique
> Produits et Procédés
> Vapor Rail Inc.
> 10655 Henri-Bourassa O.
> St-Laurent, Qc
> H4S 1A1
>
> (514) 335-4200 x2021
> (514) 335-4231 fax
>
>
>
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