We faced the same problem many years back. We suspect that the coating temperature is lower than the environment that you are working in. Try to maintain the temperature of the working area the same as the coating solution, the haze is probably the condensation from the surrounding air. An effective way to remove the haze is to blow it with a hot airgun. Hope that helps and good luck.

Regards
Yak Peng

"Bissonnette, Jean-Francois" wrote:

 This is a question for all the conformal coating specialists of thisworld.We're experiencing some problems with the application of conformal coating in high humidityconditions.  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 littleless smooth and shinny than normal.In order to avoid excess of humidity, the boards are pre-heated for 24h.  The coating used isacrylic.Anyone knows what causes this? Jean-François BissonnetteContrôle de la Qualité, ÉlectroniqueQuality Control, ElectronicsVapor Canada Inc.10655 Henri-Bourassa O.St-Laurent, QcH4S 1A1(514) 335-4200 Ext: 2021 

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