Powder Coating

What Exactly Is Powder Coating?

Powder Coating is a dry coating process that is used on a wide variety of products, representing over 20% of the total industrial finishing market. More and more companies are using powder coating for a high-quality, durable finish allowing for high production, efficiency and maintains a simple environmental compliance. Powder coatings are used as a functional (protective) and decorative finishes, which are available in an almost limitless range of colors and textures with excellent performance properties. Powder coating finishes are not only sturdy but flexible as well. They can be used on many different surfaces including metal, steel and even concrete and plastic. It is suitable for both indoor and outdoor applications and is one of the most cost-effective finish options.

What Types Of Powder Coating Are Available?

There are two types of powder coating - thermosets and thermoplastics.

Thermoplastic powder coating finishes become liquid and very soft when heated, eliminating chemical bonding making the process both reversible and reusable. These coatings tend to be thicker and more durable as compared to thermoset coatings. Because of this they can be used on unlimited products made from metal such as everything from auto parts to appliances.

Thermoset powder is quite different in that it forms a chemical bond once cured making it impossible to recycle it. It is suitable for high heat applications, such as exhaust headers, because the the bonds created prevent the paint from melting away from high heat.

How Does Powder Coating Work?

Powder coatings are based on polymer resin systems that are combined with curatives, pigments, leveling agents, flow modifiers and other additives. All of these ingredients are then mixed, cooled and then ground into a uniform powder similar to baking powder. A process called electrostatic spray deposition (ESD) is used to achieve the transfer of the powder to the metal substrate. To achieve this, the process uses a special spray gun, which applies an electrostatic charge to the powder particles which are then attracted to the grounded part.

This coating process eliminates overspray waste that can be experienced from solvent-based paints. Once the powder is applied to an even thickness, the parts are placed into a curing oven where the application of heat (up to 400 degrees F) allows the coating to chemically react to produce long molecular chains, resulting in a high cross-link density. These molecular chains are very resistant to breakdown, providing a very durable finish.

One of the biggest advantages of powder coating is that once solidified, more layers can be added to increase thickness or to apply finish layers such as clear coating. The ability to provide thicker layers means longevity and increased protection. Powder coatings are best for metal because they repel corrosive materials such as chemicals and water.

How Durable Is Powder Coating?

Powder coating provides a high-quality finish on tens of thousands of products that you come in contact with every day - things from industrial machinery to common household items to the wheels on your car/truck. You will find that powder coating is used on the roughest and toughest of machinery where rigors and abuse would quickly damage a standard liquid paint finish. Powder coated products are more resistant to poor coating quality resulting from impact, moisture, chemicals, UV light and other extreme weather conditions. This, in turn, reduces the risk of scratches, chipping, abrasions, corrosion, fading and other wear issues. Powder is much more durable than tradition liquid paint finishes while still offering the same high quality finish. Powder coating can be applied with various textures to further enhance the durability while providing very unique finished products. High gloss applications can also be achieved with the use of a finish powder clear coat application which further enhances the finish and durability.

The bottom line is that powder coating is tough, looks great, and lasts a very long time.

How Long Does Powder Coating Last?

There are a lot of things that can affect the longevity of powder coated finishes such as the quality of the preparation, type of powder used and the environment which the product is exposed. Powder coated finishes can last up to 20 years, but due to constant use, UV light exposure and outdoor environment, it is possible to break down faster. However, powder coated finishes will outlast most liquid finishes on the same materials.

Different types of coatings can have varying lifespans. Powders that have fluoropolymers and urethanes can last longer. They are designed to withstand extreme conditions and are better suited for outdoor products, while epoxy coatings, on the other hand, may last longer indoors but can break down faster when exposed to the outdoors.

What Are Other Advantages Of Powder Coating?

While we already mentioned the main advantages of durability for metal fabrication, there are other strong points that might be of interest.

Powder coated finishes are environmentally friendly as they are reusable and recyclable. Thermoplastic coatings can be reshaped very easily, unlike thermosets and the powder is also used precisely with minimal waste unlike with paint where you would experience a lot of overspray.

A typical powder coat job will have less than 5% waste and no solvents are required. No volatile organic compounds are released that may harm the environment. While it is safer to use, wearing safety equipment is still recommended, but powder does not pose as much health risk as other finishes.

You will find that the application of powder coating is usually much less than a traditional liquid based finish. This is based on several factors, such as the amount of surface preparation required and application and curing times. Since powder coating applies much thicker than a liquid paint, many surface imperfections are filled in with the coating which would require much more prep time under liquid finish applications. Cure time will also play a factor as a typical powder coated part can go from being sprayed to baked (Cured) in an oven and be ready for use in less than an hour where many liquid finishes can require as much as 24 hours between coats.

Powder coatings are also self-leveling, which provide a more natural even finish where buffing and polishing might be required to achieve the same look on a tradition liquid finish.