Blushing

Definition

Author

• Dr Lee Hitchens, Nexus

Blushing is where the conformal coating will appear to be blotchy, milky, or cloudy.

Some of the problems can include surface tackiness or greasiness, incomplete cure, poor adhesion, poor adhesion on over-coating, coating discoloration over time and poor gloss retention (matt finish).

Download our PDF guide Solving conformal coating problems in the application process now.

Examples of conformal coating blushing

Examples are shown in the images where the conformal coating where blushing has occurred.

Causes of blushing in conformal coating

Factors that influence blushing include:

Environmental Conditions: If the conformal coating is dried or cured during conditions of cool ambient temperatures, dropping temperatures, or high humidity, some conformal coatings can develop blushing.

This can be caused by the absorption of carbon dioxide and water into the conformal coating film.

How to prevent blushing in conformal coating

It is possible to minimise blushing effects:

Environmental Control: During Processing controlling the temperature and humidity in the environment and this will reduce the blushing effect in the coating.

Download our PDF guide Solving conformal coating problems in the application process now.

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