Charles -

Suggest you make a quick call to the connector supplier and ask them to
confirm their plating.  I have found many connector houses advertise "tin
plated", but actually use a plating bath that deposits about 2% of another
metal, often Bi.  If so, this solves your concern over whiskering.  A brief
SEM run would also answer this question.

Retinning in your own tinning process is possible, but it it's a cost and time
adder.  If you're dealing with a fine pitch (.025" or smaller) connector, you
will probably need to use a flowing pot with N2 inerting to help control
bridging.  (By the way, the 500C in your note is a tad on the warm side, how's
about 500F?)  You may want to consider some of the contract tinning services
who can set up to mechanically control this operation.

Soldering with Sn63 or similar will solve the problem in the termination area.
 I have not personally experienced any cases where tin whiskers have formed
between leads which were above the board surface.  Anyone else have any
experience in this area?

Regards - Kelly

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