Cracking

Description:

A series of deep cracks resembling mud cracks in a dry pond. Often in the form of three-legged stars and in no definite pattern, they are usually in the color coat and sometimes the undercoat as well.

Origin and Potential Causes:

Excessive film thickness. Excessively thick topcoats magnify normal stresses and strains which can result in cracking even under normal conditions.Materials not uniformly mixed. Insufficient flash times between coats.Incorrect use of additives. Substrate is too hot or cold. Use of coats incompatible with each other. Omitting the activator when mixing a 2K product.
 

Prevention Techniques:

Don't pile on topcoats. Allow sufficient flash and drying time between coats.Do not dry by fanning with compressed air from the spray gun. Stir all pigmented undercoats and topcoats thoroughly. Read and carefully follow recommendations in the Technical Data Sheet(s). Additives not specifically designed for a color coat may weaken the final paint film and make it more sensitive to cracking.
 

Remedy:

The affected areas must be sanded to a smooth finish, or in extreme cases removed down to the bare metal, and a full refinish system reapplied.

Detailed Image

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