Powder Coating is a coating applied as a free-flowing dry powder, designed to create a protective coating over metal components. It has various advantages – powder coating doesn’t contain solvents, so they’re safer and more environmentally friendly. Powder coating can produce thicker and more even coatings on both horizontal and vertical surfaces, and can be used for speciality coating effects thanks to their versatility.
Powder coatings are applied as a powder and held onto the surface by electrostatic charge, then heat-cured to flow and form a skin. There are two types of powder coating – thermosets and thermoplastics. Thermoset powders react to heating by forming chemical bonds and polymerising, improving its performance. Thermoplastic varieties just melt and flow together to form the final coating.
When preparing metals for powder coating, we first clean them thoroughly to remove oil, dirt and lubricants, via a variety of methods including abrasive blasting, which cleans and prepares the surface. The metal can then pre-treated with a phosphate or chromate spray to improve the bonding of the powder to the metal. Powder is then applied using an electrostatic gun, which uses both compressed air and an electrostatic charge induction unit. In some cases we will pre-heat the metal to induce bonding, although this can come with its own issues. Once the powder has been applied to the surface, it is then exposed to an elevated temperature (usually around 200C) for around 10 minutes in order to cure it and melt it against the surface, forming a solid coating.