Fluidized Bed Coating: The fluidized bed coating process consists of cleaning and preheating the metal object to be coated to a temperature only slightly above the fusion temperature of the coating material being used. The preheated object is then dipped into the fluidized vinyl powder for several seconds. The vinyl powder is maintained in a fluidized condition by an ascending column of dry air. The vinyl powder coming into contact with the heated surface adheres to the surface and fuses to form a smooth continuous surface after being removed from the bed.
Fusion and reflow can only occur if the heat capacity of the metal part is sufficient to maintain the temperature of the metal object above the fusion temperature of the vinyl powder (430°F to 450°F) after removal of the part from the bed.
The benefits of using a vinyl powder in a fluidized bed method include:
- Coatings of 5 to 40 mils without runs or sags
- Excellent salt spray resistance
- Good chemical resistance
- Cold temperature flexibility
- Black and darker colors adhere to metal substrates without a primer