Powder coating is by far the youngest of the surface finishing techniques in common use today. It was first used in Australia about 1967. It is the technique of applying dry paint to a part. The powdered paint is electrostatically charged and sprayed onto the part.

Preparation
The basis of any good coating is preparation. The vast majority of powder coating failures can be traced to a lack of a suitable preparation. The preparation treatment is different for different materials.

How is it done?
The powder is applied with an electrostatic spray gun to a part that is at earth (or ground) potential. Before the powder is sent to the gun it is fluidised:

• to separate the individual grains of powder and so improve the electrostatic charge that can be applied to the powder and
• so that the powder flows more easily to the gun.

Because the powder particles are electrostatically charged, the powder wraps around to the back of the part as it passes by towards the air offtake system. By collecting the powder, which passes by the job, and filtering it, the efficiency of the process can be increased to 95% material usage.

The powder will remain attached to the part as long as some of the electrostatic charge remains on the powder. To obtain the final solid, tough, abrasion resistant coating the powder coated items are placed in an oven and heated to temperatures that range from 160 to 210 degrees C (depending on the powder).

Under the influence of heat a thermosetting powder goes through 4 stages to full cure.

The final coating is continuous and will vary from high gloss to flat matt depending on the design of the powder by the supplier.

Why Powder Coat?
Powder coating produces a high specification coating which is relatively hard, abrasion resistant (depending on the specification) and tough.