Welding, Cutting, and Panel Bonding
Welding, Cutting, and Panel Bonding tests process selection, weld quality, and corrosion protection. Match the process to the steel grade and OEM procedure.
Processes
- GMAW short-circuit is common for mild steel; spray transfer needs higher current and is not suitable for thin vertical panels.
- STRSW reproduces factory welds; tips, current, and squeeze time must be set for the material stack.
- MIG brazing with silicon bronze is used on some high-strength and galvanized panels where fusion welding is prohibited.
- Aluminum requires dedicated equipment, wire, and cleanliness; steel contamination causes porosity.
- Cutting: use plasma, saw, or nibbler as appropriate; never cut into a closed section without checking for wiring, fuel, or SRS.
Bonding
- Structural adhesives distribute load and seal joints; observe bond-line thickness, open time, and clamp time.
- Weld-through primer protects between flanges; it is not the only corrosion protection.
- Apply cavity wax and seam sealer after welding.
Worked example
A quarter panel is replaced at a factory seam. Reasoning: the OEM procedure specifies STRSW plus structural adhesive at the flanges. The technician applies weld-through primer, sets the panel with the specified gap, makes test welds on scrap, then welds and bonds. Skipping the adhesive reduces stiffness even if the welds look good.
Traps
- Welding UHSS without OEM approval.
- Using the wrong wire on aluminum.
- Grinding welds flush and removing strength.
- Forgetting primer inside a weld flange.