8.1 Thicker Galvanizing

The galvanizing process does not eliminate the need for maintenance, but proper material selection can prolong the lifespan of the material and increase the potential for the fastener or metal connector to maintain its design strength. Increasing the thickness of the galvanized coating extends the length of time before the zinc corrodes to the point where the steel base metal begins to corrode. The two methods of producing thicker galvanized coating on connectors are:

• Fabricating connectors from steel sheet with thicker initial galvanized coating
• Galvanizing connectors after fabrication

Galvanized sheet steel is available in a variety of coating thicknesses. Several manufacturers now market common connectors in various designs fabricated with G185 to G200 grades of galvanized protection, which, compared to standard G60 or G90 grades, have zinc coatings that are two to three times thicker. Since the corrosion resistance of zinc is proportional to the thickness of the zinc, G185 to G200 connectors should last approximately two to three times longer than G60 or G90 connectors.

Thicker galvanized coatings can also be attained by using the hot-dip process after connector fabrication. Several variables can affect the thickness of hot-dip galvanizing, but the result is typically a coating of zinc similar to the coating on a G185 connector. A few types of connectors with thicker galvanized coatings are regularly available. Other connector designs are available by special order.

Figure 8 illustrates that increasing the thickness of galvanizing results in a longer service life. The extent to which service life is increased depends on the location and the amount of salt in the air, as well as pollutants such as sulfur dioxide.

Applying an additional outer coating in the factory or painting light gauge metal connectors fabricated from galvanized steel can enhance corrosion protection (see Section 8.3), and manufacturers can provide data on appropriate applications and compatible fasteners. However, paint should be used with caution because if it is scratched, it does not provide any corrosion resistance at that location.