Section IV. TROUBLESHOOTING TECHNIQUES
5-19. GENERAL PAINT FAILURES
There is a cause for every paint failure, and in most instances, the failure can be prevented by observing specific
precautions and instructions. The weather, with its humidity, heat, cold, sudden rainstorms, etc., can damage a paint film,
and for this reason the painter should take into consideration the atmospheric conditions prior to painting.
Coatings should not be applied at temperatures below 500°F (10°C).
The most frequent causes of paint failure are discussed in paragraphs 5-20 through 5-34.
5-20. ALLIGATORING AND CHECKING
Characteristics. When a rupturing of the top paint coat causes the surface to break up into irregular areas
(separated by wide cracks in alligator-hide style), the condition is referred to as "alligatoring" or "checking." Alligatoring on
a painted surface can be detected by the appearance in the top coat of small openings or ruptures which divide the
surface into small irregular areas, leaving the undercoat visible through the breaks in the top coat.
Probable Cause. Alligatoring is usually caused by too soft an undercoat or by applying a coat over an underlying
coat which has not thoroughly dried.
Corrective Measures. Remove the entire paint coat using a scraper or paint remover. Mild cases should be
thoroughly wire brushed. Before repainting, clean the surface after the old paint has been removed.
Characteristics. When the color of a previous coat is absorbed into the topcoat, the condition is called "bleeding.
Probable Causes. Bleeding is usually caused by the partial solution of the old pigment into the new coat.
Bleeding may also occur with asphalt and colored resins.
Corrective Measures. The corrective measures to be taken depend on the severity of the bleeding and the
quality of the appearance required. If bleeding is not severe, and appearance is not important, apply another coat of paint
after the previous coat (in which bleeding occurred) has dried thoroughly. If this method fails to provide an acceptable
finish, remove all paint coatings, clean the surface thoroughly, and repaint.
Characteristics. Blistering is evidenced by blister-like irregularities on the film of a painted surface, with the paint
coat detached and raised from the surface upon which it is applied.