Using powder coating with metal sculptures requires preparing the material by cleaning and degreasing it. For instance, steel requires cleaning, rinsing, etching (to remove oxides), rinsing again, grain refining an application of zinc phosphate and an acidulated rinse. Without this preparation, the sculpture may have a finish that produces a rough surface resulting in low adhesion of the powder. Other materials, like aluminum, only vary in the kind of chemical that is applied to increase adhesion.
Powder-coating guns act as a sprayer that fluidizes the powder, which means that fluid is passed up in to the powder and separates the particles. This allows them to flow more freely and retain more electrostatic charge. There are three types of guns: Corona guns, which use electricity to charge the particles; Tribo guns, which charge particles using the friction of the powder and the gun barrel; and "bell" guns, which charge the particles as they leave the bell of the gun.
Choosing your powder formulation means knowing what you want the finished product to look like and whether the work is an interior or exterior piece. If you're displaying work outside, you don't want to use an epoxy-based formula; polyester urethane coatings are durable for exterior mountings and provide a thin, smooth finishing. Acrylic is probably the most widely used because of its attractive finish and good UV protection.
Curing in high-temperature ovens to set the powder is the most time-consuming part of the process. The actual curing method depends on the size of the materials. Convection ovens are useful for smaller artworks, but can be expensive when working with larger works. Infrared curing is ideal because of the speed of the process, and the fact that little air movement means a lower chance of contamination from dirt and debris.