Powder coating has become popular among manufacturers due to its impressive performance and numerous benefits. Unlike liquid paint, powder coatings are durable and not prone to peeling when scratched or fading when exposed to UV radiation. They have zero or low volatile organic compounds (VOCs), and this makes them sustainable and environmentally friendly. To enjoy the performance benefits of powder coating, you need to ensure correct application that's characterized by a smooth finish with no contaminants. Here you will be equipped with some tips on how to achieve a smooth, even finish with powder coatings.
Control the amount of powder
Powder coatings are delivered to the desired workpiece using a powder gun. In electrostatic applications, the powder is given a negative charge while the workpiece is grounded to acquire a positive charge. As the powder is discharged from the gun, it adheres to the part due to the attraction of opposite charges. It is essential to control the amount of powder that's discharged at a particular time to avoid creating an uneven finish.
The key to spraying the right amount of powder is regulating the feed air pressure of the gun to a lower setting. Avoid setting a high pressure, as it will disperse a large amount of powder, compromising the results. You can test the gun on a reject piece to ensure that the pressure and powder volume is right before working on your piece.
Ensure the air is clean
Contaminated air can compromise your powder coatings and result in rejection of the workpiece. In a workshop setting, the air is likely to be contaminated with dust, dirt, moisture, and oil. If the quality of air compressed in the spray gun is poor, it will affect the coating process by contaminating the powder or interfering with its adherence to the workpiece.
Air quality is critical to the success of powder coating installations; therefore, you should ensure that the air compressed in the spray gun is clean. Do not finish your parts in a room where other fabrication processes such as cutting, welding, and grinding are taking place. Also, clean the workpiece thoroughly before finishing it to get rid of dust, dirt, oil, and moisture.
Separate the colors
When finishing a part with various types of colors, you may be tempted to use the same spray gun and components without cleaning them. Powder coatings may be incompatible due to differences in texture, particle sizes, resins, additives, and other compounds. Using the same components for spraying different powders may increase the risk of cross contamination in your parts. To reduce the risk of rejects, always use dedicated hoses for the different colors. Also, clean the spray guns and components before changing to a different color.