Powder coating and powder painting

Powder Coating, a Long-Lasting Coating with a Low Environmental Impact

Painting with powder coating or liquid enamels? What is the best finish for metal surfaces? Let’s learn about all the advantages of industrial powder coating.

The powder coating process is more advanced compared to liquid enamels, especially due to their ability to last longer and their lower environmental impact. In addition, powder coating also has a better appearance.

What is Powder Coating?

This is a treatment applied to metal surfaces, usually on industrial devices and components. It is applied in powder form via an electrostatic process and finished in an oven that melts the powder, distributing it uniformly on the surface.

The advantage is that a high-quality finish in terms of functionality and appearance is created.

The powder coating is not only durable and resistant, but also flexible. It can be used on different surface materials, including metal, plastic, and cement. It is suitable for both indoors and outdoors and has an excellent quality-price ratio.

Types of Powder Coating: Heat-Set and Thermoplastic

There are two types of industrial powder coating: heat-set and thermoplastic.

Thermoplastic powders become liquid and very soft when they are reheated. They are reversible and can be reused.

They also tend to be thicker and more durable than heat-set powders, which is why they are used for a large number of applications, from auto parts to refrigerators.

Heat-set powder coating instead forms a chemical bond when it is reheated and cannot be reused via a reversible process. It is used for surfaces subject to high temperatures, since it is very difficult to melt.

Between the two types, thermoplastic coatings are more costly.

The Application Process

Preparation is the first step in the application process and probably the most important, because it determines the way in which the coating will adhere to the metal surface. In fact, degreasing and subsequent washing are important.

Application then follows in three different ways.

With the first method, called fluidized bed coating, the powder is applied to metal objects heated to very high temperatures. The powder is then sprayed onto the hot surface with compressed air, where it adheres immediately and uniformly.

The other application technique is also known as electrostatic powder painting. It relies on an electrostatic spray gun, which, using the conductivity of the metal, adds a positive charge to the powder, making it adhere to the surface.

The advantage in this case is the notable savings in paint due the reduction of overspray.

The third method consists in applying the powder coating using a flame. The compressed air released to make the powder adhere is accompanied by a propane flame. The high temperature melts the powder, which then hardens via contact with the neutral metal.

This is a very effective technique, but limited only to thermoplastic powders.

How Long Does Powder Coating Last?

Starting with the assumption that this is one of the most durable surface coatings — and not only on metal surfaces (due to high abrasion resistance and corrosion protection) — its longevity depends on a series of factors: the quality of the preparation, type of powder used, and environment the surface will be exposed to after application. For example, UV rays are a major corrosive element.

The Advantages of Powder Coating

This type of finish has several positive aspects.

First, it is environmentally friendly. It is an eco-friendly alternative that may be reused and recycled, especially with the use of thermoplastic powders (this is not true of heat-set powders).

The powder is also used in precise amounts, without any waste, in contrast to liquid enamels. As well, chemical solvents are not necessary, resulting in a product that is non-toxic not only for the environment, but also for people.

It has a convenient cost over time. Although the cost of powder coatings may seem less convenient initially compared to other treatments, it is more convenient over time due to its durability and reliability.

It maintains a shiny appearance. With its ability to repel chemical substances, powder-coated surfaces are easy to clean and keep shiny.