What should be paid attention to when coating veneered birch plywood

The unique characteristics of natural veneer, such as strong water absorption, loose fiber and obvious changes in grain direction, make the pretreatment of the substrate particularly important before painting. Sanding is a key step in pretreatment. It is necessary to use the appropriate sandpaper model to sand the veneer surface multiple times to ensure a smooth and delicate surface and avoid thinning or penetration of the veneer due to excessive sanding. During the sanding process, it is necessary to strictly follow the grain operation to avoid scratches caused by sanding against the grain. At the same time, removing sand chips is also a key step to ensure that the adhesion of subsequent coatings is not affected.

The choice of coating is the basis for ensuring the quality of coating. For Veneered Birch Plywood, commonly used coating types include water-based paint, polyurethane paint (PU paint), ultraviolet paint (UV paint), nitrogen alcohol paint (NC paint) and vegetable oil wax. Water-based paint is suitable for indoor spaces with strict requirements on the emission of volatile organic compounds (VOC) due to its excellent environmental protection; PU paint is an ideal choice for high-frequency furniture parts due to its excellent wear resistance and hardness; UV paint is widely used in industrial automatic spraying production lines due to its fast curing speed and stable gloss; vegetable oil wax is suitable for log-style products that emphasize natural touch and environmental protection concepts. When choosing paint, it is necessary to comprehensively consider factors such as the use environment, design style and construction process to ensure that the final effect and function are perfectly matched.

The impact of the construction environment on the quality of coating should not be ignored. High humidity may cause the paint to turn white or dry incompletely, while low humidity may cause surface cracking. The film-forming speed of the paint will slow down in a low temperature environment, affecting adhesion and hardness; high temperature may cause the surface of the coating to dry but the inside is not dry, causing peeling or cracking. Therefore, the construction site should be kept within a relatively constant temperature and humidity range. It is usually recommended to control the temperature between 20℃ and 28℃ and the relative humidity between 50% and 70% to achieve the best coating effect.

In the coating process, the dilution ratio, spraying pressure, spray gun distance, spraying angle and number of coating layers of the coating must be strictly controlled. After each process is completed, sufficient drying time should be left to ensure that the previous coating is completely cured before the next operation. The selection and polishing of the primer is particularly critical. Its main function is to seal the fiber structure of the veneer, prevent the color difference caused by uneven penetration of the paint, and provide a balanced adhesion basis for the topcoat. After the primer dries, it needs to be carefully polished to further improve the surface flatness, eliminate tiny particles or bubbles, and provide good film-forming conditions for the topcoat.

Multi-layer coating is a common way to treat the surface of Veneered Birch Plywood, usually including primer, midcoat and topcoat. The role of the midcoat is to increase the thickness of the coating, thereby further enhancing the flatness and fullness. The topcoat layer directly determines the final gloss, color and tactile performance of the product. According to design requirements, you can choose topcoats with different gloss levels such as gloss, semi-matte or matte. Different types of topcoats reflect light differently, so it is necessary to make precise judgments based on the purpose of the space and the aesthetic needs of the user. Glossy coatings have strong color rendering effects and high visual brightness, which are suitable for display panels or spaces with strong decorative features; matte coatings have a soft texture and clear grain, which are suitable for products that emphasize natural and rustic styles; and semi-matte coatings strike a balance between the two and have a wide range of applications.