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In manufacturing, electrostatic powder coating is a type of finishing process during which dry powdered paint is applied to metal. By applying an electric charge to the paint particles as they're applied, manufacturers can create a permanent, high-quality finish. Dating back to the 1960s, electrostatic powder coating remains one of the most common powder coating processes today. It creates a finish similar to that created by wet paint, but offers a number of advantages in terms of finish quality and environmental issues.
Manufacturers may apply an electrostatic powder coating to many types of products. This type of finish is primarily used on metals ranging from steel to aluminum. It's also used to finish a variety of consumer goods, from wire shelving to lawn furniture. This powder coating is also used on cars and other vehicles, and remains a popular method of finishing exterior metal siding.
This product may contain a variety of materials, depending on the product and manufacturer. Many include an epoxy resin base, though some rely on polyester-based hybrid mixtures instead. While polyester reduces the risk of yellowing on a powder coated finish, it also offers less corrosion resistance. Acrylic products are used to create a powder coating with a high-gloss finish, while enamel-based versions are commonly used to finish electronic and mechanical equipment.
To apply an electrostatic powder coating, users use a compressed air gun. The gun applies an electric charge to each particle of paint as it enters the air. This charge causes the particles to be attracted to the surface of the metal. One the particles have attached to the metal, the object is heated until the paint particles melt or fuse to the surface.
This process offers a number of advantages over other types of finishing processes. Unlike wet paint, dry paint contains no harsh solvents. This reduces the risk of health concerns to the user, as well as to those working nearby. Powder coating also makes it easier to capture unused paint particles, which are lost during wet paint spraying. These particles can then be reused for future projects.
Electrostatic powder coating does have its limitations, however. While it can be used on most metals, it is not an effective method of finishing thermoplastics. It can also be difficult to regulate paint thickness and finish quality when using electrostatic powder coating. Thicker coats can be fairly easy to apply, while thinner coats tend to be more difficult.