How to solve the problem of coating film
The dried coating film is easy to fall off from the substrate, which means that the coating film has poor adhesion, and the phenomenon of poor adhesion may occur between the coating and the coating, or between the coating and the substrate.
(1) Causes of formation
1) Improper selection of coating products.
2) The degreasing and rust removal of the substrate is not clean, and the surface roughness value is low.
3) Improper selection of curing agent and diluent, so the volatilization rate of diluent is too fast.
4) The nozzle is too small or too large, the coating film is too thick, the volatilization time is not enough, and the spraying is too dry.
5) Too high or too low spray temperature, and too low spray surface temperature, resulting in the formation of aggregates.

(2) Solution
1) According to the relevant technical data of the product, select the appropriate coating variety.
2) Degrease the substrate before painting. The putty should be thin and firm. Every time the putty is scraped or sprayed, the bottom layer should be at least surface dry, and there should be no impurities such as water or dust.
3) Sand the repaired area and its edges with the recommended grade of sandpaper according to the product to be sprayed subsequently.
4) Select the recommended curing agent and diluent, and select the appropriate type and amount of diluent according to the ambient temperature, humidity and air circulation speed.
5) Choose the appropriate nozzle, use the correct spraying technology, and avoid spraying too thickly.
6) The sprayed wet coating has a wet feeling.
7) It is better to spray between ±20℃.
8) Under low temperature conditions, the substrate should be used to reach the same temperature as the surrounding environment before spraying.
9) According to the size of the scope, remove the defective coating film by grinding, paint stripping or sandblasting technology, etc., and re-spray.