Birchwood Casey’s Clearlok Max topcoat is a water-based blend of acrylic polymers
that forms a scuff-resistant clear coat finish on all metal surfaces. The finish’s densely packed polymer structure is designed to form a tightly adherent barrier against corrosion while enhancing the beauty and durability of the surface. It can be used on black oxide or other surface coatings, such as phosphates and antique finishes, or it can be applied directly to clean or shot-blasted metal surfaces, such are bare steel, aluminum, nickel and zinc plating.
Supplied as a liquid concentrate, the topcoat is pH neutral and nonhazardous, and is safe to apply without ventilation, the company says. It is diluted with water, applied to parts by immersion, and then dried at 70-130°F, achieving a nominal film thickness of about 0.002 inches. Once dry to the touch, the parts are ready for assembly or packaging. Full hardness is achieved in about 24 hours.
Minimum humidity resistance is 400 hrs (ASTM D1748), depending on film thickness.
For severe-duty applications that require extra corrosion resistance, the company suggests sealing the dried finish with its Dri Touch rust inhibitor to create an even more impervious barrier against humidity and corrosion.