Causes and treatment methods of coated orange peel

After the coating dries, the surface takes on the appearance of a bumpy orange peel, known as orange peel. Orange peel is common in high viscosity, high build coatings. Some coatings have high viscosity and poor self-leveling performance, such as polyester glass flake coatings and high-solid epoxy coatings. If there is no suitable spraying equipment or pressure during construction, it is very easy to observe orange peel. However, under low temperature conditions, the viscosity of the paint will increase. At this time, even the paint that is suitable for spraying at room temperature will appear orange peel, as shown in Figure 3-4-26.

Before the coating is applied to the surface of the substrate and dries, due to the action of gravity, the wet film will flow and fuse into a flat coating. If the paint film dries before it is fully blended, the surface will become uneven. In the same way, if the solvent contained in the paint itself or the added thinner volatilizes quickly, and the paint film dries before leveling, orange peel will also be formed. On the other hand, when the spraying equipment is poor or the spraying pressure is insufficient , the paint cannot be fully atomized into droplets, but touches the substrate in agglomerates, so it cannot be properly leveled, and orange peel phenomenon will also occur. When the nozzle is too close to the surface of the substrate, the pressure at the nozzle will push the wet film, causing localized paint buildup and an orange peel appearance.

In view of the above situation, if the viscosity of the paint itself is too high, it can be adjusted by adding an appropriate amount of diluent to reduce the viscosity, increase the fluidity of the coating, and avoid and reduce the orange peel phenomenon. In addition, selecting appropriate diluents according to different temperature conditions, controlling the drying time of the coating, and maintaining good spraying techniques can all reduce and avoid the chances of such defects.

Once the phenomenon of orange peel is found, after the coating is completely dry, use manual sandpaper or power Grinder to grind off the rough layer on the surface and reapply the same paint .