The galvanizing process involves coating steel with molten zinc. Logically, the molten zinc metal solidifies as it cools to form the metallurgically-bonded corrosion resistant coating. As the zinc solidifies it can cause moving parts such as drop handles, shackles, shafts, and hinges to freeze together.
To ensure moving parts’ full range of motion is maintained, best practice is to galvanize prior to assembly. If the moving parts must be galvanized after assembly, the design should incorporate increased radial clearance and all hinges to be galvanized should be of the loose-pin type.
In order to allow for full range of motion when galvanizing moving parts, consider the following:
Galvanized moving parts (such as drop-handles, shackles, and shafts), a radial clearance of not less than 1/16” (1.5 mm) is suggested to ensure full freedom of movement.- After hinges are galvanized, it is recommended an undersized pin be used to account for the zinc coating. If desired, hinge pinholes may be reamed 1/32” (0.8 mm) after galvanizing to permit the use of regular-sized pins.
- If the galvanizing process freezes the moving parts, they can be reheated to allow them to work freely. Reheating may cause localized discoloration of the galvanized coating, but does not diminish the corrosion protection.
For optimum performance, assembling moving parts after galvanizing is almost always preferred.
