Fluorescence Helps Identify Coating Defects

Fluorescence Helps Identify Coating Defects Jim Deardorff has preached the gospel of reducing rust and corrosion through high-quality metal finishes for more than 30 years. With 14 stories in FARM SHOW, mostly on products and techniques to protect metal, he’s our resident coatings expert. One of his favorite methods for preventing rust is to apply a primer with a fluorescence additive (Vol. 16, No. 5) and shine a black light on it. His concept is now being introduced commercially. “Rust-Oleum Corporation has introduced V7400, the first self-inspector coating,” says Deardorff of Superior Coatings. “V7400 is a high-solids alkyd coating that can be brushed, rolled, or sprayed. It produces a smooth, hard, durable finish, guaranteed to stop rust for two years or more.” What makes V7400 special is that it’s formulated with a defect indicator based on UV-activated blacklight fluorescence. The additive was developed by Deardorff in the early 1990s. At the time, he was working with the University of Missouri and Ciba-Geigy in Tarrytown, N.Y., to produce a fluorescent response for paintings and coatings. With the additive in the paint, workers using a black light can identify film-coverage defects much more effectively and efficiently. “The average worker with 20/20 vision can locate a coating defect approximately 50 microns in size,” says Deardorff. “However, it requires good lighting and adequate time for a careful visual inspection. The same worker using a black light with this additive in place can easily locate the same defect, even in low light or during production painting operations.” He lists some of the benefits, including ensuring complete coverage of welds, joints, and corners. Using a black light also reduces material waste from over-application, improves maintenance recoating, and reduces premature coating failure. He recommends The uvBeast black light (Vol. 48, No. 2). Deardorff estimates that black-light enhancement improves defect detection by up to 1,000% over the human eye alone. Undetected defects allow rust to develop. “According to a University of Windsor study, rust can penetrate metal up to 2 in. per year,” says Deardorff. “Detecting defects stops rust before it can start. With a good finish, you can reduce unplanned repairs and early replacement expense and enhance trade-in and resale value.” Contact: FARM SHOW Followup, Superior Coatings Co., 205 McCormick St., Chillicothe, Mo. 64601 (ph 660-973-9489; info@classicblast.com; www.classicblast.com).

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