CoatingsPro Magazine

MAY 2017

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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Page 48 of 84

48 MAY 2017 COATINGSPROMAG.COM hangar was ~35,000 square feet (3,251.6 m 2 ), and Cook believed the most efficient way to tackle the job was for the crew to work on only one of the two hangars at a time. Wearing 3M disposable respirators, glasses, gloves, steel- toed boots, safety vests, and hard hats, the crew started work by grinding the newly installed concrete surface using Diamatic's 780PRO and the STI Prep/Master 3030 from Substrate Technology, Inc. Both are electrical-driven grinders. "It goes three or four times faster than using one grinder," Cook said. From there, the crew shot blasted the surface with Blastrac's walk-behind 1-10DS and BW Manufacturing's SCB-1600, a ride-on machine. Once the grinding and shot blasting were complete, the crew used vacuums from Pullman Ermator and Ruwac to clean up before moving on to the applica- tion processes. Approved for Take-Off e successful surface preparation enabled the crew to begin installing the flooring system within days. Using 18-inch (45.7 cm) rollers and squeegees, they first applied a vapor barrier from KOSTER at an average of 15 mils (381.0 microns), taking into account the client's concerns over existing high moisture readings. After allowing the vapor barrier to cure overnight, the crew then installed Flowcrete's Flowprime primer at an average of 10 mils (254.0 microns), effectively dividing each hangar into three sections to set the table for the epoxy mortar. "If we did it all at once, the primer would be dry by the end," Cook explained. "W hen you're laying the epoxy mortar, you lay it into the wet Flowprime." As each section received the prime coat, the crew then quickly followed with the Flowtex epoxy floor mortar at ¼ inch (0.6 cm) of thickness on average. e epoxy mortar was mixed in a large metal screed box and installed with a power trowel and hand trowels, making it the only layer of the complex system not applied with rollers and squeegees. "It's like an assembly line," Cook said. "ere's a large mixing station, where you have three or four guys mixing the Flowprime. Once we have a certain portion, a couple guys lay the Flowprime in front. en we have one guy in the mixing station who delivers the Flowtex to the floor, with three or four guys on the floor troweling the Flowtex into the Flowprime. en we have others pulling the box forward and hand troweling the edges." Cook described the trowel application as a two-step process. "W hen we power trowel, there are two processes," he explained. "One guy knocks it down, trying to get it flat and smooth. en the other trowel guy right behind him — we call him 'finishing guy' — his blades are flat. His jobs are to smooth it out and close out the trowel, and fix any small things that the first guy didn't get." Once troweling was completed on all three sections in each hangar, the crew spent one day to prefill all of the seams and any other areas that needed filled. From there, they were ready to wrap up phase one of the project with the application of Flowcoat OP, a thixotropic epoxy coating to deliver a sealing effect over the trowel. "You add the thixotropic to stop the epoxy from completely soaking into the trowel," Cook said. "It's an additive that goes into the epoxy that makes it less flowable. at way, when you apply it onto the troweled mortar, it soaks in a little — but it sits on top. If I just went straight from the mortar to the inter- mediate coat, it would look good at first, but then an hour or two later, it would completely soak into the [mortar]. You'd lose that coat." As a result, while the crew applied the Flowcoat OP at 16‒20 mils (406.4‒508.0 microns), only 5‒6 mils (127.0‒152.4 microns) actually remained on top of the floor, Cook estimated. e rest went into the mortar. At that point, after about four weeks of work, Cook 's crew vacated the site for more than a month and allowed the other subcontractors to complete their assignments. e intermediate Hangar Floors Phase two of the coating application included two coats of Flowcoat SF41, two coats of Flowseal PU Gloss (pigmented and then clear), and one coat of Flowseal PU Satin on the perimeters. Safety gear included 3M disposable respirators while on surface prep. During the rest of the time, they wore glasses, gloves, steel-toed boots, safety vests, and hard hats when necessary.

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