Improper coating method and 

uneven film thickness.

Strengthen   operator training to maintain proper spraying speed, spraying distance,   coating sequence and coating frequency.

Before the paint   is used, the settled pigment has not been stirred up or stirred   insufficiently, resulting in a decrease in covering power.

Stir thoroughly before use 

and during coating process.

The paint was   not diluted in accordance with the construction process instructions during   the paint dilution process. Then over-diluted or sprayed paint film is too   thin.

Appropriately   increase the construction viscosity or increase the number of sprays to   increase the thickness of the paint film.

The color contrast between the 

primer and topcoat is too great.

The color of the   primer should be as close as possible to the color of the topcoat.