Parts are powder coated through electrostatic spray or immersion into an electrostatically or non-electrostatically charged fluidized bed of powder. Electrostatic dip beds are rare and are usually small, as it could be unsafe to electrically charge a large mass of powder. In addition to electrostatic dip beds, industry uses non-electrostatic dip beds. With these dip beds, the hot parts enter the bed and powder suspended as particulates melts onto the parts. Parts must have certain geometric figures, as an electrostatic charge does not help wrap the powder to the parts. This method works well with flat surfaces or like materials as they lack areas that prohibit the powder from coating and fusing to the part. There is little powder control. Anytime a part is heated to get paint to stick to it, the ability to apply powder at a controlled and reasonable rate is lost. By contrast, industry widely applies powder coating by spraying the powder. The method is versatile and provides better control over coating thickness.
By Gary Conner
By George N Bullen FSME