One、Why does powder coating fall off?
Besides process-related issues, the cause of powder falling from powder coatings can also be material-related. Before spraying, powder coatings need to be diluted with a solvent and water. If the dilution ratio is too high, the coating film will become thin, failing to cover the substrate and causing detachment. Qualified products provide clear dilution ratios, which is theoretically the most scientific approach. However, consumers should not expect workers to strictly adhere to the specified ratios. The experience of construction personnel is also valuable, and appropriate adjustments can be made based on the specific environment. However, it is important to control the dilution ratio. If the dilution ratio is too high, detachment and cracking may occur. If the cause is determined, consumers can request the contractor to redo the renovation.
Typically, it takes 7 days for powder coating to fully cure on the wall surface. To avoid rushing the process, it is recommended to apply an appropriate primer to the substrate to seal it, thereby improving the adhesion of the topcoat and effectively preventing issues such as powder detachment.
Two. What to do if the powder falls off after applying powder coating?
1、For electrostatic spraying of powder coatings, it is advisable to use materials with high dielectric constants. This will significantly increase the adhesion of the powder. Because, the lower the dielectric constant of the powder, the easier it is for the particles to become charged, but also easier for them to lose their charge. This manifests as poor adhesion of the powder to the substrate, resulting in detachment even with slight vibrations.
2. When the powder particles are expelled from the nozzle using compressed air, and directed towards the workpiece (the cathode) using electrostatic force, the coating adheres firmly to the workpiece. Typically, a coating thickness of 50-100μm can be achieved within a few seconds. once the powder layer reaches a certain thickness, a thick electrostatic shielding layer is formed on the surface, preventing subsequent negative particles from accumulating, thus stopping further coating thickening. The coating application process is complete.