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STEEL 2019


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10 STEEL SURFACES 2019 COATINGSPROMAG.COM Preparation Makes Perfect With a plan mapped out and people in place, the first phase of an application project typically involves preparing the surface and achieving a certain surface profile. "Your substrate preparation is very important because you have to make sure there are no oils or soluble salts," said PMC's Mahaffey. "at creates corrosion issues. You've got that surface, and then you have to have an acceptable profile so you get a good mechanical bond of the coating to the substrate." Blasting, high-pressure waterjetting, and power tool cleaning are among the more popular techniques for prepping steel substrates in various ways, with companies such as BlastPro Manufacturing, Blastrac, and Jetstream of Houston, LLC among the specialists. "One of the greatest concerns we have is surface prepa- ration," said Belzona's Nisill. "It tends to make or break a project when it's coating steel. As a manufacturer, we can design and develop products that have better features, but ultimately, it always comes back to the level and the detail of the preparation." According to Sherwin-Williams' Morris, one key consid- eration is the content or exposure of a given asset. "Surface preparation and surface profile are in direct correlation to the commodity that's stored on the interior of a structure, the generic type of coating selected, and probably even more so the temperature at which it's stored. A ll organic films are permeable to some extent. e thicker the film, the greater the depth of profile needed to ensure that we've got a good mechanical bond," he said. As with the planning phases, understanding the surrounding environment is critical. "W hen we recommend work procedures, we're always looking to [answer] what is this piece of steel and what is the environment that it's in, because there are different recommendations if it's just general environmental exposure compared to vessel or a tank to where the steel or the coating would be immersed in fluid," said Belzona's Nisill. For immersion service, Belzona often recommends abrasive blasting to a recognized standard, such as NACE No. 2/Society for Protective Coatings (SSPC) Surface Preparation (SP) 10: Near-White Metal Blasting, followed by an angular profile. For non-immersion service, the NACE No. 3/SSPC-SP 6: Commercial Blast Cleaning standard is often sufficient. If the location precludes blasting equipment, the SSPC-SP 11: Power Tool Cleaning to Bare Metal standard can be used for hand tools. Generally, the technical data sheet for the selected coating system should contain information about the neces- sary level of preparation. "Steel is fairly simplistic," added Sherwin-Williams' Morris. "As long as it's clean, dry, and profiled, you shouldn't have a lot of challenges." It is important to wear gloves when blasting to avoid potential contamination issues. "W hen you have applicators working with no gloves, sometimes they' ll have done the blasting, and then somebody comes down and puts their hand on it," said Belzona's Nisill. "And we've seen failures due to a hand print and the associated salt and greases from that." In addition, Rowland suggests potential salt testing in select environments. "If you're working in an area with high salt content in the air, like a coastal environment, for example, it's imperative to check for surface cleanliness to make sure the substrate is free of things like nitrates, sulfates, and chlorides," he said. CHLOR*RID and HoldTight both offer options to help rid surfaces of salts. Sherwin-Williams' Morris points to testing kits from providers such as Elcometer for chlorides and sulfides. "A lot of contractors may not be aware that there are non-visible Steely Resolve continued from page 8 Surface prep is crucial on all coating projects. "Steel is fairly simplistic," said Kevin Morris, global market director at Sherwin-Williams. "As long as it's clean, dry, and profiled, you shouldn't have a lot of challenges." "One of the greatest concerns we have is surface preparation," said Barry Nisill, vice president of business development at Belzona. "It tends to make or break a project when it's coating steel." Blasting and waterjetting may be options. Steely Resolve

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