Yes, moisture.  You should really be spraying in a humidity controlled
environment.  
Jim Marsico
Senior Engineer
Production Engineering
EDO Electronics Systems Group
[log in to unmask] <mailto:[log in to unmask]> 


        -----Original Message-----
        From:   Bissonnette, Jean-Francois [SMTP:[log in to unmask]]
        Sent:   Monday, June 18, 2001 11:36 AM
        To:     [log in to unmask]
        Subject:        [TN] Conformal coating:  white haze

        This is a question for all the conformal coating specialists of this
        world.
         
        We're experiencing some problems with the application of conformal
coating in high humidity
        conditions.  Just after the application is finished, some kind of
white haze appears in the coating.
        It disappears a little be during curing but some of it stays.  The
finish of the coating is then a little
        less smooth and shinny than normal.
         
        In order to avoid excess of humidity, the boards are pre-heated for
24h.  The coating used is
        acrylic.
         
        Anyone knows what causes this?
         
         
        Jean-François Bissonnette
        Contrôle de la Qualité, Électronique
        Quality Control, Electronics
        Vapor Canada Inc.
        10655 Henri-Bourassa O.
        St-Laurent, Qc
        H4S 1A1
        (514) 335-4200 Ext: 2021
         


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