According to Sherwin-Williams, coatings with high loadings of zinc dust are difficult to apply on steel and can take too long to dry. Coatings with a lower zinc load can dry quickly and also allow for a smoother finish, however, decreased zinc dust can raise performance concerns such as inadequate corrosion protection.
With 76 percent zinc dust in the dry film, Sherwin-Williams’ Zinc Clad II Plus FG is a “field-grade” inorganic, zinc-rich coating for steel that is said to be fast drying and to perform comparably to other inorganic zinc coatings with higher zinc loadings. It also offers a more uniform finish, faster dry-to-handle time and a longer pot life than competitors, the company says. In addition, it features a volatile organic compound level of less than 340 g/L and meets a Class B slip rating.
For use over prepared blasted steel, the coating self-heals to resume protection if damaged in the field and also provides sacrificial protection by the same mechanism as galvanizing, forming an inorganic barrier to moisture and harsh solvents that may cause damage to the substrate.
Zinc Clad II Plus FG can be applied as a one-coat maintenance coating or as a permanent primer for steel substrates in severe corrosive environments. It is compatible with most Sherwin-Williams epoxies, acrylics and polysiloxanes.