When the Mountaire Farms feed and poultry operation in Millsboro, Delaware, decided to refinish several existing grain storage tanks, its owners were not about to “play chicken” with an unproven coating system. “They wanted an affordable finish coating that could protect their storage tanks against corrosion from a combination of salt and humidity in the air,” according to Todd Guntner, Tnemec coating consultant. “The material also needed to dry fall because on windy days, airborne grain particles can embed into a wet coating and cause problems.”
What ended up being used was an acrylic polymer, Series 30 Spra-Saf EN, that had proven effective in protecting elevated water tanks in Ocean City, Maryland, which is 30 miles from Millsboro. “The exposure there is very severe,” Guntner reported. “Near the beach, the air is moisture- and salt-laden, so the faster the coating cures, the better off you are. Spra-Saf EN is very fast-curing.”
“This was the first use of this system on grain tanks in the area,” Guntner noted. “The coating contractor for the project introduced me to the owner and I showed him our data sheet and the performance we’re getting down in Ocean City where this coating system has 8-plus years of service life. The economy of the product was also a factor in their decision. They wanted a coating that would get the job done at a reasonable cost per square foot.”
Prior to the finish coat being applied, the tanks were prepared by high-pressure wash and detergent cleaning at 3,200 psi to remove surface contaminants and loose paint. Rusted areas were removed in accordance with SSPC-SP3 Power Tool Cleaning. The tanks were then spot primed with a polyamidoamine epoxy, Series 135 Chembuild, followed by two finish coats of Spra-Saf EN spray-applied at 2.0 to 4.0 mils thickness each.
In addition to providing corrosion protection and weathering properties, the acrylic polymer finish is formulated to minimize mildew growth on the paint film, Guntner said. The first three tanks were completed in August 2005 during the first phase of the overall project which includes more than 6.2 million bushels of grain storage – which IS chicken feed in this business.