Just wanted to thank everyone profusely for their feedback and info!  This
really helps!

Best regards-  Bill C

-----Original Message-----
From: [log in to unmask] [mailto:[log in to unmask]]
Sent: Monday, April 09, 2001 10:52 PM
To: [log in to unmask]; [log in to unmask]
Subject: Re: [TN] funky stuff on white tin


Bill,
    I work with the Omikron White Tin on a daily basis.  Your guess is
exactly right, the rinsing of the board after the white tin is deposited is
not adequate.  First of all the white tin bath is a "yellowish" color.  Also

the chemistry is "sticky" if allowed to dry and not rinsed thoroughly.
Finally if the solution is dried but left in the hole it will ooze back out
and on to the surface when it sees heat during assembly.  It would then
appear black in color and probably "crispy."
    As with most final finishes good rinsing is critical, the white tin bath

is acidic and it is never a good idea to leave an acidic solution on the
surface of a circuit board for extended periods of time, especially a final
finish.  Good rinsing is a key step, especially with plugged via holes.

Steve Wentz
Florida CirTech Inc.

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