The phenomenon that the coating is damaged by external effects and loses its integrity is called. If the coated object is not protected during transportation, transfer and use, it is often prone to bumps, scratches and coating defects. It includes the following film defects.
Scratch: After the coating film is dried, it is subjected to external force, etc., resulting in streaky scars.
Contact scars: Scars caused by contact with hoses, hands, etc. before the coating film is dry.
Pecking: After the coating film is dried, it is affected by external force, etc., resulting in point-like scars.
Grinding scratches: scratches on the coating film caused by improper use of grinding tools.
Filing: Streaky scars left when a painted surface is trimmed with a file.
Pen scratches: marks left on the painted surface with a pen are called scratches (instrument: pencil Hardness Tester).
1. Etiology
1) The wet coating film is affected by the external environment, and its complete state is changed.
2) The dry coating film is subject to mechanical scratches. The coated object is poorly packaged, and the coating film is damaged by external force or mutual impact.
3) The marking pen does not meet the requirements.
4) Impacted by wind, sand and foreign objects during use (related instruments: impact Tester).
5) The cracking resistance of the coating is poor.
2. Prevention and treatment
1) It is strictly forbidden to contact with foreign objects before the coating is dry (instrument: drying time Tester).
2) Strengthen the protection of the coated object during storage, transportation and assembly, and bumping is strictly prohibited. Where the hanger (or station equipment) is in contact with the object to be coated, it should be protected by softening. During the assembly process, the coating surface should be protected by a protective cover, so that it can be handled with care, and attention should be paid to hoisting.
3) Marks made with a pen (such as chalk) on the object to be painted before painting must be removed during pre-cleaning. It is strictly forbidden to use ordinary pen or chalk to mark the coating.
4) When finishing the surface of the object to be coated and the surface of the coating, the grinding tools or files should be selected and operated correctly to prevent damage to the coating film due to improper operation.
5) According to the use conditions of the coated object, choose a coating with good cracking resistance and scratch resistance.
