The correct application of the coating is vital to achieve many of the coating's intrinsic properties. Additionally, the applicator will have a great deal of influence over the final weatherability, corrosion resistance, appearance, and many other attributes of the coating system.
Dry Film Thickness (DFT) is measured in microns (millionths of a metre, 1 micron = 1/1000 millimetre) or in mils (thousandths of an inch, 1 mil = 1/1000 inch).
1 mil is approximately 25 microns. Manufacturers design coatings with a DFT in mind and being below or above the recommended range can have undesirable results.
Coverage may be measured in many ways: weight per area, or area per weight. More simply, where the parts being sprayed are the same, it can be measured by parts per box.
Powder is supposed to flow like water in the container; correctly fluidised powder should appear like simmering water. There are various tests for powder coating fluidity, most notably the 'Sames Test' (AFNOR) which gives a R value to a powder coating.
Depending on the choice of nozzle, the powder coating spray pattern will be different. However all powder coating spray clouds should be an even, soft stream of powder, free from surges and spitting.
Fluidisation is good, but the powder is not being fed to the gun in a smooth continuous flow. These problems may be caused by blockages in the feed system, including hoses, venturi and spray gun equipment.