What is Powder Coating
Powder coating is an advanced method of applying a decorative and protective finish to a wide range of metal products that are used by both industries and consumers. The powder used for the process is a mixture of finely ground particles of pigment and resin, which is sprayed onto a surface to be coated and then baked in a curing oven. The result is a uniform, durable, high-quality, and attractive finish.
The main difference between a conventional liquid paint and a powder coating is that the powder coating does not require a solvent to keep the binder and filler parts in a liquid suspension form. The coating is typically applied electrostatically and is then cured under heat to allow it to flow and form a “skin”.
It Looks Like Paint But It Acts Like Armor! It makes products durable, attractive, and scratch-resistant. We are surrounded by items that are powder coated. For example, patio furniture , garden tools, mail boxes, kitchen appliances, automotive trim, and wire closet shelving are just a few of many! Highway and bridge construction materials must be epoxy powder coated for corrosion protection. Notices the next time you’re out for a drive that they many bridges are “lime green” in color.
The powder coating process involves three key steps:
- Preparation of the surface to be coated.
Preparation of the surface is fairly simple. It needs to be free of dirt, grease, oil, rust and other contaminants. This can be achieved by blasting the surface with abrasives and/or using a chemical cleaning agent. Once the surface is clean, the next step starts.
- Application of the coating material.
Although other application methods are sometimes used, the most popular powder coating technique involves the use of a powder “gun.” The gun is used to impart an electrostatic charge to the powder particles, and it uses compressed air to transfer them onto the object being coated—much like a spray gun propels wet paint. This process is generally more efficient and easier to perform than traditional wet spraying because the powder is attracted to the surface being covered and the coating material tends to even itself out as it melts during the curing process. The material that does not adhere to the surface is usually trapped by filters mounted in the exhaust system of the spray enclosure. The overspray can either be discarded (in “spray-to-waste” type systems) or collected and saved for re-use (in more expensive “reclamation” type systems)
- Heated curing of the applied coating material.
Curing is done in an industrial oven designed for powder coating use. The most popular “walk in” sized ovens use LP or natural gas fuel. Smaller ovens sometimes use electric heating elements. There are also models that use infrared panels or gas catalytic infrared heating. Almost all powder coatings cure at a temperature of 325° to 425° Fahrenheit.
It has many advantages over the traditional WET painting:
Cost and other benefits:
Powder coating gives consumers, businesses, and industry one of the most economical, longest-lasting, and most color-durable quality finishes available.
Powder coated surfaces are more resistant to chipping, scratching, fading, and wearing than other finishes. Color selection is virtually unlimited with high and low gloss, metallic, and clear finishes available. And colors stay bright and vibrant longer. Texture selections range from smooth surfaces to a wrinkled or matte finish, and rough textures designed for hiding surface imperfections.
Powder coating is also highly protective of our environment. While liquid finishes contain solvents which have pollutants known as volatile organic compounds (VOCs), powder coating contains no solvents and releases negligible amounts, if any, of VOCs into the atmosphere. Thus, there is no longer a need for finishers to buy costly pollution control equipment. In addition, most powder coating overspray that does not adhere to the part can be retrieved and reused, virtually eliminating the waste commonly found in liquid finishing processes.