Kathy,

if it's cosmetic and only due to humidity then it should disappear upon
heating at say 110C for 30 - 60 minutes and driving off the moisture.

Andrew Hoggan
BBA Associates Ltd
www.bba-associates.com


-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Kathy Kuhlow
Sent: Wednesday, July 18, 2001 06:24
To: [log in to unmask]
Subject: [TN] White residue from conformal coating


What causes white residues after conformal coating?  The coating is an
acrylic and after the first coat there appears to be a white residue and
after the 24 hour cure the coating appears very dull and still has some of
the white residues.  The residues almost look like water flux residue but it
isn't.  The supplier that the coating was purchased from says it is strictly
humidity related and only a cosmetic issue.  There is no visible loss of
adhesion.  The solder mask is a LPI matte finish.  Can this be part of the
problem?

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