Q. I specify the materials used by a commercial painting contractor. One of our customers owns several coal-fired power plants, and one of his plants is adjacent to a river. He wants to use an anticorrosive paint to coat the structural steel and the rail track on the conveyor that transports coal from coal barges tied up at the dock to the plant storage bin. We have been looking for an online solution as to what paint to use on the steel structure and the steel rail tracks of the conveyor system. Can you offer any solutions to this problem? —K.S.
A. If the structure is already in place, your customer could paint the structural steel using either a zinc silicate followed by an epoxy primer or a two-component zinc-rich epoxy primer, but not the rail track surfaces. If it is a new conveyor system, not yet installed, the structural steel could be pretreated by phosphatizing, galvanizing or painting using a zinc silicate primer. The zinc silicate primer must be applied directly to the metal. In either case, the metal must be prepared by degreasing and sand blasting to remove any rust and oily soils before painting. After applying the prime coats, any high-quality topcoat such as an acrylic, polyester or polyurethane enamel will provide long-lasting protection.
On the bearing surfaces of the steel track, where the steel wheels contact the rails, however, nothing other than a coating like Teflon or a polyamide will last for any length of time without wearing off.