Blair,
The condition you are seeing is called "blush" and as you say, usually 
occurs when humidity is high or condensation is occurring during the 
liquid phase of application.  You can usually get rid of it by baking the 
boards and I have seen it go away with time.  Improving your environmental 
controls in the area would help.

Doug Pauls



From:   Blair Hogg <[log in to unmask]>
To:     <[log in to unmask]>
Date:   08/29/2012 09:05 AM
Subject:        [TN] Cloudy Conformal Coating
Sent by:        TechNet <[log in to unmask]>



I'm hoping that Technetters can share some light on an issue that we 
occasionally experience here - we coat some of our boards with 1B73 
conformal coating, for some we have a spary machine, others a sprayed by 
hand. 

Every so often we will process some board through coating and they will 
have a cloudy / milky appearance in the coating. We have been told 
previously that this happens when humidity is up, since our manual spray 
coating area is not in an air-conditioned environment. 

Anyone else ever have this problem? How did you fix it? 

Thanks,

Blair




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