1. Causes
The air trapped under the paint film expands and separates the paint film from the substrate. The specific reasons are as follows:
A. Improper construction method for putty, NC putty and primer causes the air is trapped in the paint film;
B. Improper handling of feather edges at the joints of the paint film;
C. Cover the lacquer film on the gap or dead corner to form a gap under the lacquer film;
D. Poor quality thinner used or insufficient thinner, or the pressure on the compressed air is too high, dry spray, etc., forming pores or bubbles in the primer;
E. The substrate is not properly processed and sealed, especially when spraying the surface of glass fiber reinforced plastics.
2. Prevention
A. Use putty, NC putty or primer correctly
B. Make feather edges correctly
C. Avoid spraying the paint too thick at one time, and ensure that the paint penetrates into the gaps and dead corners.
D. Be sure to use the recommended thinner and operate according to the correct spraying process. The primer also needs to be sprayed thin and wet.
E. Check the substrate if there are pores, especially the bubbles in the surface adhesive layer of FRP. It is best to carefully remove air bubbles and seal the substrate.
F. When baking the paint film, prevent the temperature from being too high.
3. Repair:
According to the depth of the bubbles, all the corresponding paint film is polished off, and the lower layer defects are repaired, and then the paint is sprayed again.
