The galvanized pilings in the tidal area had suffered extensive loss of steel thickness. The loss occurred in the entire tidal zone and about 1 foot [0.3 m] above the high-tide mark. Even in areas where the galvanization hadn’t failed, it was heavily weathered,” said John Griffin of Grace Coatings.

Grace Coatings specializes in coatings jobs with areas of rusted steel where environmental issues limit blasting and coating options. With the knowledge gleaned from previous projects, Griffin and his team were ready to accept the challenge to clean and coat the pilings. They proposed using a specialized hot water pressure washer to prepare the surface of the pilings, priming the steel with LifeGuard Active Rust Primer, and coating the substrate with two coats of PPG’s polysiloxane PSX 700 to provide long-term coatings protection.

Tidal Watch
According to Griffin, the Carolina Yacht Club wanted real-life proof that Grace Coatings’ plan was the right solution for its dock pilings. During the month of September, a single piling was hot water pressure washed and the LifeGuard primer and the PSX 700 coating were applied. After five months, the piling was inspected and the results were more than favorable. The Carolina Yacht Club gave Grace Coatings the green light to proceed with the job.

The team, which numbered between two and four men, started the job in early March. On one hand the timing was great, considering it was the offseason, so the dock area wasn’t crowded.  On the other hand, Mother Nature was less than cooperative at times. “Cold and rainy days limited work a bit during the two-month duration of the project,” said Griffin. 

Inclement weather was not the only consideration when it came to timing. Work on the pilings could only take place during low tide, so the hours were very limited. “We started painting one hour before low tide to ensure plenty of dry time. Luckily, the LifeGuard and the PSX 700 are both fast-cure coatings. This made securing the pilings at low tide easy,” stated Griffin. All in all, the Grace Coatings crew cleaned, primed, and painted 50 pilings, each 2 feet (0.6 m) in diameter. According to Griffin, depending on the condition of the galvanized steel, the crew worked on a range of 6 to 8 feet (1.8–2.4 m) in length per piling.

In Hot Water
Working over the water in the Charleston Harbor required extreme caution — life vests were worn during the job — and compliance with environmental regulations. “We couldn’t spray any coatings, so both the primer and the PSX 700 were brush- and roller-applied. Most significantly, we couldn’t use any cleaning detergents or solvents. We could only use fresh water for the surface preparation process,” said Griffin.

This is where the Cam Spray MCB7042H CB Series oil-fired hot water pressure washer came into play. As stated by Griffin, this pressure washer is an indispensable piece of equipment for jobs such as the one at the Carolina Yacht Club. The hot water pressure washer is portable and requires no electricity as the water is heated by an oil-fired burner that uses diesel fuel or kerosene to achieve 140° F (60° C). “It is 7,000 psi [48.3 MPa] with a turbo nozzle to remove all loose rust and scale. The pressure washer provides a unique combination of high pressure with heat in a small portable package that can reach most any job,” said Griffin. And since hot water acts as a natural emulsifier, no detergents were used, making the surface prep method compliant with environmental regulations and containment unnecessary.

Just in Time
Once a piling was pressure washed (and hand tooled where needed), it was time for the crew to apply the LifeGuard Active Rust Primer. LifeGuard Active Rust Primer is a water-borne, acrylic primer with natural tannins that allow it to adhere directly to a clean steel surface. “It has a high tolerance for salt and is suitable for harsh marine and industrial environments. It also dries to the touch in 15 minutes and is fully cured in 2 hours. This made it the perfect choice for the dock pilings,” said Griffin. In addition, the primer is biodegradable and environmentally friendly.

Working around the tide cycle, the crew brush-applied two coats of the LifeGuard primer at 2–3 mils (50.8–76.2 microns) wet film thickness.  The two coats were typically applied in one day, with the crew coming back the next day to brush-apply the PPG PSX 700 polysiloxane coating at a wet film thickness of 4–5 mils (101.6–127.0 microns). The PSX 700 is a fast-drying epoxy that is long-lasting, ultraviolet (UV)-resistant, and slick, an important property for standing up to the friction of the dock moving up and down with the tide cycles. A second coat of the PSX 700 was applied again at a wet film thickness of 4–5 mils (101.6–127.0 microns) the following day at low tide. It also should be mentioned that the crew rinsed the pilings with fresh water between tide cycles and before applying the next layer of coating.

Smooth Sailing
According to Griffin, the job at the Carolina Yacht Club was a success because of many factors, not the least of which was strategic planning on the part of his crew. They also used the right tools and materials for the project. 

“Coating products that offer long-term protection are a must when dealing with galvanized steel in and around marinas, docks, and harbors. With both the LifeGuard primer and the PPG PSX 700, we know that the coatings are manufactured especially to endure the harsh marine environment. And they cure very fast, which was very important when working around the tide cycles. Also, using the Cam Spray hot water pressure washer was huge on this job — we were able to properly prep the pilings and be compliant with the environmental regulations that exist anytime you are working over water,” stated Griffin.