Glassflake reinforced CoatingsFlake reinforcement is most effective at providing a barrier to permeation of the lining. The aligned flakes
make the path of water or other contaminants through the resin much longer. Since the flakes are
not permeable, water molecules must travel a much greater distance, and the resistance of the composite
is greatly increased. This barrier effect is important for high temperature immersion service.
Trowel-applied glass flake-reinforced systems provide the highest permeation resistance since large
glass flakes up to 1⁄8 in. (3 mm) in diameter can be incorporated. These linings are rolled
after application to minimize trapped air and assist in flake alignment. These systems normally are
applied in 2 or more layers. Thickness ranges from 60 to 160 mils (11⁄2to 4 mm) for temperature service up to 200 F (93 C). Smaller glass or mica flakes are used in spray-applied systems. The
flakes, though not as well aligned, still provide a high degree of reinforcement and increased permeation resistance. Spray application reduces applied cost.
Spray-applied systems typically withstand immersion temperatures of 130 to 150 F (54 to 66 C) when applied in 2 to 3 coats at 30 to 80 mils (3⁄4 to 2 mm). In nonimmersion conditions, flake-reinforced polyester linings can withstand temperatures of 300 to 350 F (149 to 177 C), while vinyl esters can withstand 350 to 400 F (177 to 204 C). Thinner systems of 2 coats at 20 mils (1⁄2 mm) normally are recommended for mild, nonimmersion applications (Fig. 4).