There are many finishing options for product manufacturers. Products may be coated to provide corrosion resistance, improve the appearance, or enhance the performance of items. Of the many finishes available to manufacturers, two similar finishing processes stand out. These are powder coating and electrophoretic deposition (EPD), sometimes referred to as e-coating. In this guide, we will introduce the similarities and differences between the two finishing options, helping you to decide which option is best for your specific finishing needs.
Powder Coating vs. E-Coating
Two of the most popular finishes available to manufacturers are powder coating and e-coating or EPD. While there are similarities between the two, each has its own unique processes and applications.
Powder
Powder coating is the process by which items are coated with a durable, attractive finish. Unlike wet painting methods, powder coating uses a dry pigment powder and an electrical current to coat metal substrates (the items to be coated). Pigment powders are made of plastic resins, typically epoxy or polyester resins. Hybrid blends of the two resins are also available. The powder is positively charged by the application gun, and the item to be coated is given a negative charge. Powder flows from the application gun, coating the part with an even layer of pigment. Because electrical charges are used, recesses and contours are adequately covered. Once the powder is applied, the parts are cured in an oven, fusing the powder into a glass-like coating. Powdered pigments are available in thousands of colors and glosses, including those that enhance grip while reducing fingerprinting.
Powder coating is used in the automotive and agricultural industries to protect parts from corrosion. Once cured, the coat is UV-resistant and maintains its attractive look for years. Outdoor products such as railings, patio furniture, and sporting goods are also commonly powder coated.
EPD (E-Coating)
E-Coating is a similar process in that it uses powdered pigment particles to provide a coating. Unlike powder coating, however, e-coating uses a liquid bath containing pigments, water-based carriers, and epoxy resins. The item to be coated is suspended in the bath, and an electrical charge is applied, attracting the pigment particles to the item. By varying the voltage and the duration of the liquid bath submersion, coaters can alter the thickness to desired levels. Once a sufficient thickness is achieved, the parts are removed from the bath and cured in an oven.
E-coating is ideal for parts that have complex contours and recesses. The pigments adhere evenly to all surfaces. E-coatings tend to be thinner than their powder coated counterparts as well. E-coating is typically used as an intermediate step in the finishing process, serving as a sort of primer coating underneath wet-painted finishes. This gives the coated part enhanced corrosion protection. E-coating may also be used to simulate expensive metals, such as coating cheaper aluminum parts with a finish that mimics brass or stainless steel.
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