In the manufacture of welded pieces it is necessary to eliminate the scales or projections produced by the welds, since they are stuck to the surfaces and will produce roughness imperfections and lack of a good finish in the galvanizing after galvanizing. The pieces must come as clean as possible. .
In the case of flat surfaces with a large surface in contact with each other, discontinuous welding must be avoided, if the contact gap is very narrow, since Zn does not enter the overlap area, but the water before or after galvanizing, of so that later the rust “flows” through those points. If it is continuous welding, drainage holes must be left to avoid explosions that affect the safety of the operators, since pockets or air bubbles in a piece submerged in molten Zn at 450º C suppose an instantaneous evacuation of the air causing explosions.