Electro-Plated Zinc (ASTM B633)
This type of coating is recommended for indoor use in relatively dry areas. This process deposits a coating
of zinc on the steel or iron by electrolysis from a bath of zinc salts. This coating is pure zinc and
adheres to the steel or iron with a molecular bond. A maximum of .5 mills of zinc can be applied using
Pre-Galvanized Zinc (ASTM A653)
This type of coating is suitable for extended exposure in dry or mildly corrosive atmospheres, but not generally
recommended for outdoor use, or in industrial environments. This coating is also referred to as “mill
galvanized” or “hot-dip mill galvanized”. This process continuously rolls steel coils or sheets through
molten zinc. The steel is then cut or slit to size. Coating thickness of .90 ounces per square foot of steel
surface (referred to as G90). Cut edges are not zinc coated, however, zinc near the uncoated steel becomes a
sacrificial anode, which protects the bare areas after a short period of time.
Hot-Dip Galvanized (ASTM 123)
This type of coating provides extended corrosion protection for steel and iron products exposed to
extreme humidity commonly evident in outdoor exposure or in uncontrolled atmospheric conditions. This
coating provides superior corrosion resistance to that of electro-plating. The process calls for the steel or
iron product to be completely immersed into a bath of molten zinc, which creates a metallurgical bond.
The minimum coating thickness is 1.5 ounces per square foot per side (3 ounces per square foot of steel
or iron). Caution should be taken when specifying Hot-Dip Galvanizing on certain products. Products
with threaded components should either have the threads protected from the galvanizing process or
chase the threads subsequent to hot-dipping. Products with critical size tolerances should account for the
thickness of the coating.
COPPER-GARD finish for copper tubing installations.
The finish provides superior corrosion protection and insulates against dissimilar metal contact, thus preventing
electrolysis. The process applies a baked-on epoxy paint to steel stampings and iron castings. In the three-step
process, the parts are zinc plated to .0002” thick, an epoxy copper colored powder is then applied by an
electrostatic method, and finally, the coated parts are baked at 180 degrees for 20 minutes.
This coating is designed for copper tubing installations. The coating is intended to identify the product size
only. This finish is not intended for corrosion resistance.
This coating is intended to support chrome plated pipe and provides corrosion resistance for commercial
installations such as hospitals, schools and prisons.