8 common problems in coating construction and emergency treatment methods
1, vertical flow:
When coating on the vertical surface, the coating film flows downward, and the convex portion has a poor coating effect.
Cause: The coating may be too thick or the coating concentration is too high, the spray gun gas is too large, the paint is too much, and the nozzle is too close to the coating.
Treatment method: Dilute the viscosity, adjust the gun gas, the pressure is 3.5-4.5kg/m2, the pressure is appropriate and the output is suitable (15cm-20cm).
2, brush marks:
After the application, the coating film has a strip-like unevenness.
Cause: During construction, the viscosity is too high and the wet film is recoated.
Treatment method: adjust the paint to the appropriate viscosity. When applying, the base film should be basically dry, and the brush should not be too strong.
3, pinhole:
After the coating film is dried, the coated surface exhibits a small pore shape, and the small pores are caused by the substrate on the surface.
Cause: The coating film is too thick, the drying temperature is too high, and the coated material has moisture and dust paint.
Treatment method: The thickness of one spray should not be too thick, control the proper drying temperature, and keep the coated objects free from dust and the like.
4, dry spray phenomenon:
When the coating is sprayed, the atomized coating is dried before it is applied, and when it is attached, a rough coating is formed.
Cause: The distance between the spray nozzle and the object to be coated is too far, and the air pressure of the spray gun is too high.
Treatment method: adjust the distance between the spray gun mouth and the object to be coated, about 15cm-20cm, the pressure is adjusted to 3.5-4.5kg/m2.
5. Whitening phenomenon:
The surface of the film was pale and had no expected gloss.
Cause: The humidity is too high (more than 80%), the thinner is too fast, and the coated object is too cold.
Treatment method: The coating humidity should be 80% or more, or 5-10% anti-white water can be added. Use a quick-drying thinner, and the coated material should not be too cold.
6, peeling off:
The film is dropped from the surface of the object to be coated.
Cause: The substrate has wax, oil, water, etc., the undercoat is not dried and then coated, the substrate is too smooth, the wall has been powdered or inferior to the soil, and the adhesion is not enough.
Treatment method: thoroughly remove the substrate to ensure that there are no wax, oil, water and other debris. The old wall that has been powdered must be cleaned up; use oily soil, or water-based soil to be leveled, completely dry and then coated.
7, orange peel phenomenon:
The coating film is not smooth, like an orange peel coating film.
Cause: The diluent evaporates too quickly, the spray pressure is not constant or the pressure is too high, the blowing distance is too far, the spray is too thick, and the bottom layer is not dry and then coated.
Treatment method: Use appropriate dilution solution to control the pressure of the spray gun. The distance should be moderate. Do not apply thick coating once, and the bottom layer is completely dry and then coated.
8, fading phenomenon:
After a few days of coating, the color partially faded and the color was uneven.
Cause: The new one is not completely dry, the alkalinity is too heavy, causing the color to fall back.
Treatment: The new wall should be painted one month later and the epoxy primer should be applied to the bottom.
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