What Does Paint Failure Mean?
Paint failure is the loss or reduction of paint's coating bond strength between coats and the substrate. Paint failure occurs when a protective coating of paint fails to protect the substrate, provide an aesthetic look or serve some other intended function. The initiation of paint failure is often slow, but once started it propagates quickly
Because paint is used as corrosion protection, paint failure increases the rate of corrosion and material damage.
Paint failure is also known as paint adhesion loss.
Corrosionpedia Explains Paint Failure
Paints or coatings are the principal methods of corrosion protection for all steel structures. All paints, and particularly many of the more advanced coatings, are complex chemical mixtures that must react in place on the surface on which they are applied. These are applied to the surface as a very thin film, which must withstand adverse environments. When this film deteriorates, it is known as paint failure. Paint failure may be due to paint shrinkage and movement over the surface or moisture penetration of the paint layers at pinholes and cracks.
The primary causes of paint failure are:
- Inadequate surface preparation
- Improper application of paints
- Sun exposure
- Inappropriate design
Most paint failures are related to moisture and inadequate surface preparation. There are many types of paint failure, including:
- Alligatoring: Cracked paint which resembles alligator skin. This is due to application of too many layers of paint.
- Bleeding: This is a surface discoloration from water or water-soluble dyes located in or on the painted surface.
- Blistering: This is caused by moisture behind paint, or by painting over wet or damp surfaces.
- Blooming (blushing): This is moisture getting into varnish, shellac or lacquer.
- Peeling : Strips or sections of paint peel loose from the surface, usually due to moisture and/or inadequate surface preparation.
- Cracking, checking, flaking, or crazing: Paint loses its elasticity, crazes, then cracks, especially where paint is thick or multi-layered.