Metal Finishing Guide Book


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Page 263 of 903

Fig. 2. Typical electrocoat tank with conveyor. tween the electrocoat and the substrate and to enhance corrosion protection. A final deionized water rinse is applied to the parts prior to the electrocoat tank. Dry-off ovens are generally not required. Electrocoating Bath The electrocoat bath consists of 80 to 90% deionized water and 10 to 20% paint solids. The deionized water acts as the carrier for paint solids, which consists of resins, pigment, and small amounts of solvents. The resin is the backbone of the final paint film and provides properties such as corrosion protection and ultraviolet durability. Pigments provide color, gloss, and corrosion protection as well. Solvents help ensure smooth film appearance and application. During the electrocoat process (see Fig. 2), paint is applied to a part at a certain film thickness, which is regulated by the amount of voltage applied. The deposition is self-limiting and slows down as the part becomes electrically insulated 258

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