Powder coating is a method of covering a surface with an aesthetic-looking powder coat that will protect the surface from rust, corrosion, scratches, and any other damage. Metals are most commonly powder coated, but some powder coating services also undertake the coating of other materials such as wood, glass, composites, MDF, and plastic.

The process involved in powder coating these materials is different than for metal as they can melt or burn when exposed to a high degree of heat. It is necessary therefore to impart these materials with a heat withstanding facility before the powder coating process.

Understanding Powder Coating Process

The first step in powder coating is to prepare the surface. In the case of metal, you should sandblast it in a dry environment to remove dirt, rust, oil, mill scale, and any old coatings. It is important that you only do this in a dry environment as the sandblasting process removes the metal’s surface oxidation and renders it vulnerable to quick rusting. This being the case, don’t delay in applying the zinc-based primer and in carrying out the powder application.

Powder coating is best done for small parts that you can spray on quickly. Once you have primed the surface, heat the parts in an oven to melt the primer. Then remove for the powder coating. It is essential to deposit an even layer of polymer powder on the surface. You can do this with an electrostatic spray in a controlled setting. The sprayed-on powder doesn’t stick to the surface in the usual sense, but, in fact, attaches itself to the surface due to electrostatic attraction. That is, the powder carries a positive charge as soon as the spray fires it onto the surface and the surface already carries a negative charge, and this results in, as mentioned, an electrostatic attraction.

Around 60 to 70 percent of the powder that you spray on the surface will attach itself to it. You can reclaim and recycle the powder that falls off. This means there is no wastage in the powder coating process.

Also, you can make do with only one coat, and there is no question of spraying too thick or too thin. Since the powder attaches itself to the surface by electrostatic attraction, only a single layer of positively charged powder particles will attach to the surface, and the surface will repel all further particles even if they bear a positive charge. The single layer is at least ten times as thick as a layer of liquid paint and is sufficient protection for the surface.

After spraying, place the powder coated parts in the oven for the curing process. Avoid touching the powder-coated surface or causing it to rub or bump against anything as this can disturb the powder layer.

The hard polymer coat that then forms over the surface is made up of long, strong, and flexible molecular chains. Along with being around ten times thicker than a layer of wet paint, it is very durable and can withstand vibrations, jolts, and bumps without getting chipped or scratched.

The coating also increases the surface’s resistance to corrosion, and it does not fade away over time. Better yet, powder coating is an inexpensive process, and you can get a variety of colorful, textural finishes. As soon as you remove the part from the oven, you can use it as per your requirement. You can do this within 20 minutes.

The Benefits and Drawbacks of Powder Coating

While spraying, it is necessary to wear a protective face mask and to avoid inhaling or getting the powder on your skin. Another issue is that the maintenance of the oven for the curing process can be expensive. Also, once you have cured a powder coated part, you cannot retouch its surface to change or improve it.

On the plus side, powder coating is free from harmful chemical compounds like solvents and volatile organic compounds. You only need one layer, and it is durable and long-lasting. It is also inexpensive, easy to apply, and with no wastage. Powder coating, therefore, finds wide usage, and powder coating services remain in high demand in the military and industrial sectors.