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Why are There Pinholes in the Spray Paint of Sheet Metal Processing?

Apr. 17, 2021

As a Sheet Metal CNC Bending Processing Supplier, share it with you. In sheet metal processing, why are there pinholes in the spray paint of sheet metal processing, and how to solve them?

Sheet Metal CNC Stamping Processing

Sheet Metal CNC Stamping Processing

Condition: Needle-like holes, deep and middle paint.

Reasons: glass fiber substrate; insufficient mixing of polyester filler (putty); solvent bubbles still remain on the polished surface; insufficient primer of polyester filler (putty).

Prevention method: Mix the polyester filler (putty) thoroughly; do not polish the solvent bubble or completely remove the problematic paint film; fill with enough polyester filler (putty).

Remedy: remove the defective topcoat; apply polyester filler (putty) after sanding; re-spray the topcoat after spraying the primer.

Condition: The paint surface shows small bubbles and blisters.

Reason: The solvent air is hidden in the paint film, and then escapes, leaving blisters. The common causes are as follows: the paint film is sprayed too thick, and the hardener or thinner is used too fast; Incorrect spray air pressure; insufficient static time before heating and drying or insufficient airflow in the paint booth.

Preventive methods: use the correct spray viscosity, spray air pressure, and nozzle diameter; use appropriate hardeners and thinners; give enough rest time. Regularly check the air pressure and humidity in the barn.

Remedy: After drying, sanding, re-spray the intermediate paint on the affected area, and spray the top paint after sanding.

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