The Powdercoating Process
The powder coat process is a metal finishing process that can replace traditional wet painting when superior performance is required.
Powder coating is a metal finishing process that was pioneered in the 1950’s to replace traditional wet painting when superior performance is required. Over time it has developed into a common, even preferred process for the manufacturing industry, certain specialty groups such as automotive, racing, and sporting goods, as well as hobbyists and homeowners.
Beginning with proper metal pretreatment, powder coating process may include mechanical abrasive and/or chemically cleaning for the production of a surface finish optimized for coating. Best results are obtained when any rust and existing coatings are removed. The powder coat process is best suited to all-metal parts, weldments, and assemblies. Plastic, rubber, wood, ceramic, glass, fabric, and similar non-metallics are typically not coated. Similarly, lead soldered parts may not withstand the curing temperature.
Before powder application, parts are hung on portable racks. Hanging the parts ensures that the powder coat can be applied uniformly with no further handling or disturbances. Powder is applied in a clean containment booth to prevent contamination with dust or powders of other colors. Parts are electrically grounded, and the dry powder is then sprayed using a system which electrically charges the powder particles. The charged powder is attracted by, and attaches to the metal surface.
After parts are coated with dry powder, the parts (on their racks) are moved into a curing oven. As the coated parts heat up, the powder gels and flows to produce the characteristic powder coat finish. As thermosetting powder coatings reach their maximum curing temperature, a chemical reaction called cross-linking takes place. At this point the parts can be removed from the oven, cooled in ambient air, and be immediately put in service.