CoatingsPro Magazine

JUL 2018

CoatingsPro offers an in-depth look at coatings based on case studies, successful business operation, new products, industry news, and the safe and profitable use of coatings and equipment.

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52 JULY 2018 COATINGSPROMAG.COM Not First Oktoberfest! With the blasting done, the crew vacuumed, swept with push brooms, and repeated until they were confident the tanks were clean — generally about six times. ey resisted the urge to blow down the substrate with compressed air so as not to create an unwanted dust storm inside the tank. e disposed material — spent coal slag and Latiglas parti- cles — was stored on site in 2,200-pound (997.9 kg) capacity woven fabric sacks. Ritter collected representative samples of the material in 1-gallon (3.79 L) press-seal plastic bags and drove them to a nearby testing laboratory. Two weeks later, the lab declared the material non-hazardous. Only then did a licensed hauling contractor truck the material to a landfill for proper disposal. Had the samples tested hazardous, the material would have ended up in a hazardous waste treatment storage and disposal facility (TSDF). Hazardous waste hauling and disposal charges at TSDFs generally cost much more than typical hauling and landfill tipping fees. After testing the anchor profile with a DeFelsko PosiTector SPG (surface profile gage), the crew geared up to spray apply approximately 20 mils (508.0 microns) of Munkadur GL straight to metal. ere was one problem. In this working brewery, the cellar ambients couldn't be raised off the 38 °F (3.3 °C) mark, and these beer tanks were stone cold! Now, Enerfab PC&L always makes sure that the Munkadur GL leaves their Graco Extreme 68:1 plural component pump at the correct temperature, but it's important that the coatings substrate is the correct temperature, too. "To get the GL up to temperature, we use drum heaters to bring the 55-gallon [208.2 L] drums of A and B side materials to 158 °F [70.0 °C]," said Hartgraves. "Heated hoses make sure the two GL components hit the plural component pump at 176 °F [80.0 °C]." But none of that means jack if the tank walls are 38 °F (3.3 °C), more than 20 °F (6.7 °C) below GL specs! To work around cold cellar temperatures, the crews wrapped the tank exteriors with foil-backed insulation to prevent heat loss, and they fired up Dayton electric space heaters inside the tanks. e hard part was timing the gradual temperature rise to coincide with the coatings crew's arrival. Luckily, this is not Enerfab PC&L's first Oktoberfest! "Our guys on both shifts know exactly when to crank up the heat when they leave to bring the tank slightly above 62 °F [16.7 °C]," said Hartgraves. "at way, the next shift can turn the heaters off at the proper time so the tank 's internal air temperature settles into our preferred application range of 58 °F to 62 °F [14.4‒16.7 °C]." Hop to It With ambient and feed temperatures under control, it was time for Enerfab PC&L to hop to it. Workers first lined the tank floors with brown paper. "We lay paper down so overspray doesn't fall to the floor and cure before we get a chance to coat it properly," Hartgraves said. "We work from back to front, applying a single 20-mil [508.0 microns] coat of GL in two passes, crosshatched at 90 degrees with a 50 percent overlap." Enerfab PC&L nozzle men know how to hold their 525 tips. "If you don't keep the tip perpendicular to the substrate, you' ll get disproportionate film build," Hartgraves said. "It's also important to keep the nozzle 12 inches [30.5 cm] from surface. Tips are designed that way." Hartgraves explained that the first number of the tip size, multiplied by two, tells the correct width of the spray pattern at 12 inches (30.5 cm). So a 525 tip yields a 10-inch (25.4 cm) pattern from 12 inches (30.5 cm) away. "Some people want to pull back farther than 12 inches [30.5 cm] to get more coverage," said Hartgraves, "But it's better to move up to a 725 if you want a 14-inch [35.6 cm] fan." Pressure to finish loomed large, but the PC&L spray crew worked hard and helped bring this project in on time and safely. ey wore Ty vek suits by DuPont during the spray application portion of the job. A Frosty One Before tossing her gear in her truck and heading toward the next project, Ritter made sure the brewery maintenance crew had a firm grasp on Munkadur GL's clean in place (CIP) proce- dure. e coating system's main purpose is to form a slick surface that deters microbial growth, which may contaminate The Enerfab crew completed the project in 4½ months. "I'm certain this coating system will allow the brewery to produce great beer for years to come," said Operation Manager Nathan Hartgraves. "On the last day during the close-out meeting, they told me we had taken care of all their expectations and that they were satisfied," said Enerfab's Project Manager Rachel Ritter. Brewery Tank Recoat

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