Virtually any product with a painted surface needs some form of pretreatment. With powder as a topcoat, pretreatment should leave the raw part as clean as possible. A powder’s performance is based directly on the pretreatment it receives. Needed testing relies on the pretreatment structure as the backbone of the topcoat. Before beginning this chapter’s discussion, a few definitions are in order: Pretreatment is the process of chemically cleaning and etching a substrate (part), before coating it (with wet or powder paint) to remove surface tension, soils, and contaminants. Organic soils are oils, waxes, mill oils, lubricants, cooling oils, and drawing compounds. Inorganic soils are rust (oxides) and dirt. Phosphate coatings are produced on ferrous and nonferrous metal surfaces.
By Gary Conner
By George N Bullen FSME