Powder coatings are used on everything from tractors and cranes to gas and electric ranges, refrigerator doors, washing machines, microwave ovens, dishwashers, home façades, mailboxes, and more.
Powder coatings are safe, economical, durable, and friendlier to the environment than most paint coatings. An entire industry has sprung up around the practice of powder coating in order to ensure that standards met.
Here is a look at what powder coating is and how the industry maintains standards.
What is powder coating?
Unlike spray paint, powder coating is a dry finishing process. Introduced to North America more than 40 years ago, powder coating is now one of the most popular ways to protect metal against corrosion, chemicals, scratches, and more. In fact, powder coating represents more than 15% of the total industrial finishing market and is used in everything from protective to decorative finishes. Powder coatings are available in a nearly limitless range of colours and textures. Recent advances in powder coating have even allowed the process to be applied to some woods.
Powder coatings are based on polymer resin systems. By combining curative’s, pigments, levelling agents, flow modifiers, and other additives, powder coatings can be applied in a uniform thickness to any metal that will hold an electrostatic charge. The ingredients are all melted together, cooled, and then ground into a uniform powder that isn’t all that different from regular baking flour. This powder is then sprayed on to a metal substrate, which has been electrostatically charged, and baked in a curing oven where the addition of heat leads to a chemical reaction that produces a highly cross-linked polymer.
The biggest advantage to powder coating is the fact that produces a high quality finish that is exceptionally durable. Powder coatings stand up better than traditional spray paint to impact, moisture, chemicals, ultraviolet light, and other extreme weather conditions. Powder coatings are less likely to be scratched, chipped, and corroded. They are also less likely to fade and to wear through over time.
VOCs (volatile organic compounds) are solvents found in most liquid finishes that are necessary to keep them liquid until they are applied and allowed to dry. During the drying process of liquid paints, VOCs are released into the atmosphere. These chemicals are dangerous to human health and to other components of the ecosystem and thus are heavily regulated by the U.S. Environmental Protection Agency. In fact, there has been an effort in recent years to reduce or eliminate VOCs from liquid paints. Because of the way they are produced, powder coatings have almost no VOCs to begin with and thus are more beneficial to the environment.
Why powder coating is regulated
The powder coating industry is regulated for two basic reasons. First, the industry is regulated to ensure that a certain level of quality is achieved by professional applications. Unlike spray paint and other liquid coatings, applying a powder coating requires a certain level of technical expertise. For instance, the quality of a powder coating can be affected by the type of solvent used to clean the components, by the electrostatic charge used to attract the powder to the item being painted, and by the specific type of powder used. Polyester powder coatings, for instance, are far more durable for exterior applications than epoxy powder coatings. In order to ensure the highest level of service is provided, the industry regulates itself and offers education and credentialing services to people interested in applying powder coatings.
The second reason that the powder coating industry is regulated is to ensure compliance with applicable local, state, federal, and international laws. Though powder coating is more environmentally friendly than many types of liquid coatings, it is still necessary for the industry to be regulated to ensure that it maintains compliance with law.
Major applications of powder coating
Key markets for powder coatings include agriculture, construction, appliances, electrical, functional, and lawn and garden. The functional market includes things like oil transmission pipelines, reinforcing steel bars, valves, electric motor windings, and fire hydrants. Powder coatings are also used on everything from playground equipment to bicycle frames and wheels. Many people don’t realise this, but powder coatings are frequently applied to ski poles, exercise equipment, metal toys, desk accessories, wheelchairs, vending machines, gasoline pumps, and even satellite dishes.
Harley Atkinson is a metal fabrication worker. He enjoys writing about his experiences in the industry online. You can find his posts on many manufacturing and metal fabrication sites.