Symptoms: Alligatoring and Checking"Alligatoring" is a failure in the paint film where it takes on a cracking pattern of deep relief resembling a reptile's skin, such as that of an alligator. "Checking" is a similar failure but is less severe and is characterized by long, fairly evenly spaced cracks in the paint film having shallow relief or depth. Occasionally checking may become severe in some areas and a deeper crack or split in the paint will occur.
Potential Causes (Alligatoring):
- A second coat of paint was applied over a first coat of primer or paint base coat before it dried.
- A second coat of paint was applied over an incompatible paint such as a glossy paint or a hard oil enamel over a latex based paint.
- Oil based paints naturally aging and losing the little elasticity the paint film originally had, therefore it cracks due to fluctuations in temperature.
Potential Causes (Checking):- Natural aging of several layers of older oil based paint. As the material having been painted shrinks and expands over time (usually wood), the paint has to move and as it loses elasticity, it checks.
Possible Repairs:- The fix is the same for both problems.
- Remove the old paint, sand, prime and repaint with flexible latex based paint.
- Use high quality latex paint.
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