Steel Coatings Articles

Recoat Heats up on Steel Exhaust Stacks

Photos courtesy of PennCoat
Vendor Team

Graco Inc.
Equipment supplier
88 11th Ave. NE
Minneapolis, MN 55413
(612) 623-6000

HoldTight Solutions
Material manufacturer
P.O. Box 27907
Houston, TX 77227
(800) 319-8802

Coatings contractor
1921 McFarland Dr.
Landisville, PA 17538
(888) 600-5220

PPG Industries
Coatings supplier
3800 W 143rd St.
Cleveland, OH 44111
(216) 671-0050

Torbo by Keizer Technologies Americas
Equipment manufacturer
10908 S. Pipeline Rd.
Euless, TX 76040
(817) 685-7090

Tyvek by DuPont
Safety equipment
P.O. Box 80728
Wilmington, DE 19880
(800) 448-9835

United Rentals
Equipment supplier
2684 Reach Rd.
Williamsport, PA 17701
(814) 237-3325

Industrial Fabrications, Inc. needed a job corrected after a previous coating job started to rust. The industrial company makes mufflers that reduce sound coming out of generators, and they had metal exhaust stacks that were rusting. Of course, the stacks had to be prepared and coated on site.

The company found Landisville, Pennsylvania-based coatings contractor PennCoat and project managers Jeff Neal and Mike Speece through an internet search. Industrial Fabrications contacted PennCoat through its website, but when the coatings contractors arrived onsite, they found a few hurdles to overcome on this recoat project.

Constant Coordination

“The stacks were painted on site, but the painting process was not done at the right millage,” Speece said. “They were installed at a generation site for natural gas, and they started to have some rusting. They contacted us to get our input and do the project and repair the coating.”

Once the job was secured, Neal and Speece got the PennCoat crew ready to work. They landed on the jobsite at the beginning of August 2014. PennCoat, which has between 15 and 20 employees, used a crew of four to five for this job.

The job lasted 240 hours, or about a week and a half, Neal said. But before the crew could begin the actual work, there was some preparation that needed to be done. Because the stacks were on site, there was a lot of nearby equipment that needed to be protected.

“There was a lot of covering up and protecting of any surrounding equipment,” Speece said. “The job was at the back side of their building, and they had piping coming out of the building, electrical equipment sitting on the ground, motors and more piping sitting on the ground, and that all had to be covered up during the blasting and painting process. There was a lot of preparation involved to be sure you were painting what you wanted to be painting.”

The wind proved to be an extra challenge, even in just the covering phase. “We covered up the entire back wall, but then it was windy that weekend, and so when we came back most of the covering had been removed because of the wind,” Neal said. “So we had to do that twice.”

The second time around, the crew was better prepared. “We used extra tape to reinforce the plastic,” Neal said. Once the covering was done, the job could begin. First the crew had to prepare the substrate by removing all of the previous coating. To do this, they relied on Torbo USA’s turbo blaster that uses a grit mixed with water. “So you don't get any dust or emissions,” Neal said. “We couldn’t make any dust, which is why we chose to prep with the Torbo Blaster.” But the jobsite’s location made this a challenge.

“We didn't have any access to water, so we had to haul over 1,000 gallons (3,785 L) to be sure we could prepare properly,” Neal said.

To haul all of that water, the crew used a constant system of filling and transporting giant tanks. They took a 275-gallon (1,041 L) tank to their shop, filled it up there, and then brought it to the jobsite. When that was used up, they did it all over again.

The hard work paid off, because the blaster worked perfectly. Next, the crew used HoldTight’s surface preparation to reduce the risk of any flash rusting.

“That way we didn’t have to worry about rust appearing before the next coat,” Neal said. “Overnight it can get the flash rusting, so that’s when HoldTight came into effect to help eliminate that,” Speece added. “The coating also does allow for a little bit of flash rusting; it can handle that.” Neal said the HoldTight is not a product they use very often, but it worked perfectly for this job. Finally, the crew was ready to apply coating.

Perfect Performance

The crew went with PPG’s Hi-Temp 1027, a coating product that can resist extremely high continuous dry temperatures. The ability to withstand temperatures was key for the client and the types of jobs it does, Speece said.

“The coating can withstand temperatures of up to 1,200° F (549° C) intermittent,” he said. “Where these mufflers are, they’re getting a lot of exhaust out of the generators, and it can get pretty hot, so they need a coating on there that can withstand the heat. So that’s why we specified that coating.”

Neal said that like the HoldTight, he does not often use PPG but was satisfied with its performance. “It worked perfectly for this job,” he said.

The crew applied two 6-mil (152 microns) coats to achieve an average 12-mil (305 microns) thickness. The crew coated four 25-foot-tall (7.6 m) stacks using two Graco 7900 sprayers.

“We did a lot of stripe coating of nuts and bolts; you have to give those a stripe coat before you spray on there because that would be an area where you have some rusting,” Speece said.

To navigate around all of the piping on the jobsite, the crew used a 40-foot (12 m) lift rented from United Rentals. When using the lift, the crew used fall protection. Facemasks, safety glasses, and gloves were also worn at all times, Neal said.

When the Client’s Happy

When the job was done less than two weeks later, Speece and Neal were very pleased with the result. Even better, the client was satisfied. “They were happy; everything turned out really well,” Speece said. “Everybody was satisfied; they signed off on the project, we were paid, and the job was completed.”

Speece said his crew and their process were prepared for the job, even with its particular challenges. “Overall, the process went really well,” he said. “We’re a pretty industrial operation, but this job wasn’t anything way out of the ordinary that we couldn’t handle. It had nothing we hadn’t run into before. On every job you have factors; you just have to know how to handle them.”

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