California Fencing Contractor (C-13) License Practice Exam

After galvanizing, welding patches disturb the protective zinc coating, so the repaired area must be re-protected to prevent corrosion. The completed welds are ground smooth, and the area is cleaned of any loose or burnt zinc. The restoration step described here uses tin-lead solder (50-50 solder) to coat the cleaned patch. Soldering the area creates a continuous metallic film that covers the weld and blends with the surrounding zinc-coated surface, providing immediate corrosion resistance in the field until a more permanent galvanizing touch-up can be applied. Using a zinc dip coat would require a dipping process, and galvanized paint can be used but may not provide the same quick, uniform field repair as soldering. Hence, applying 50-50 solder is the described method for neatly coating the repaired area.