Fitz’s Atlas 2™


of coating defects


Coating Defects BUBBLESOR BUBBLING


Description:


Bubbles within a paint film appear as small blisters. These may be intact or broken (to leave a crater). Can be found in excessively thick paint films, especially if spray applied, and also with roller application.This should not be confused with blistering.


Probable Causes: Trapped air/solvent within the coating which is not released before the surface dries. Air entrainment during mixing. High ambient temperature during application. Also seen when overcoating antifouling without removal of the leached layer and zinc silicates. Can be found with factory applied coatings where application is by dipping, electrodeposition or roller coating.


Prevention:


Spray application - adjust viscosity with thinners and follow data sheet requirements for maximum application temperature. Use correct mixing equipment to ensure air is not stirred in during mixing. Apply a mist coat. Add defoaming agent to emulsion paints.


Repair:


Depending on extent and severity of bubbling, abrade or remove the offending coat(s) and recoat.


4-37


E SAMPLE


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