Lincoln Electric - Tips for Welding Sheet Metal Panels

Welding sheet metal panels, like any welding application, requires proper technique and equipment. While TIG welding is known as a more a precise procedure, it also requires a more advanced level of skill. When welding thinner metals, such as sheet metal panels, the main objective is to achieve optimal penetration while avoiding warping and burn through, and delivering a quality weld with a clean appearance.

The proper MIG welding tips and techniques for novice welders or individuals looking to occasionally weld are listed below to help anyone achieve a high level of success in collision and auto repair applications.
PreparationAlways consider safety first. Make sure you have appropriate protective equipment such as a welding helmet, safety glasses with side shields, gloves and long sleeves. Before beginning any automotive welding application, make sure the battery on your car or truck is disconnected.

Properly secure your ground clamp. Position your ground clamp as close as possible to the area where welding is being conducted to avoid damaging sensitive equipment such as door hinges, wiring, and sensors. Make sure the ground clamp is connected to clean metal. Paint and rust are both are electrical insulators. These materials do not allow the welding current to flow properly, resulting in an unstable welding arc.

Equipment
Choose the smallest wire possible. A smaller wire, between .025 and .035 inches in diameter requires less heat to melt. This reduces heat to the base metal, eliminating burn through. With less filler metal, the user has more control over the weld bead, delivering an overall cleaner weld appearance.

Use a machine with a short circuit transfer process. Machines with this capability, such as Lincoln Electric’s line of Power MIG® wire feeder welders, should be set with a wire feed speed between 150-250 inches per minute and 15-22 volts of input power. With these settings, the process allows users to weld on both thick and thin material in all positions with a controlled current, making it easier to produce a clean weld. Control of the current minimizes spatter while delivering optimal penetration for low heat input applications.

Use 75/25 gas (Argon-CO2) blends. This combination reduces penetration for thinner metals that require less heat and preparation. Argon distributes less heat than 100 percent CO2. Having the proper wire and gas combination lowers overall consumable costs.
　
Application
Avoid long welds. Use only short tack welds when possible to dissipate heat evenly. For long seams or when continuous welds are necessary, start tack welding at the middle and proceed along and skip weld or back step to distribute heat evenly and avoid stress buildup, warping and heat distortion.

Despite the challenges of welding thin metal, following these basic principles and utilizing the proper equipment can make sheet metal welding easy even for the beginner welder or home hobbyist.



Lon Damon
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