On immersion the air tr avels up the underside surfaces causing air pock ets at each plate On withdr aw al zinc tr avels or flows down the upper surfaces pooling at each plate T here will alw ays be air or zinc tr aps even on channels Remember where zinc pools so will flux Angles crop plates before welding hole or cut corners Angle fabrications zinc or air tr ap zinc pock ets air pock ets 22