Which technique helps reduce heat input when patching a car panel with MIG welding?

• A. Use long, continuous welds
• B. Use short tack and stitch welds with cooling breaks
• C. Weld with maximum voltage
• D. Weld from both sides with no clamps

Answer: (C)

Reducing heat input during MIG patching is key to preventing distortion and burn-through. The most effective approach is to use short tack and stitch welds with cooling breaks. By depositing welds in small segments and letting the panel cool between passes, you limit the amount of heat entering the metal at any one time. This keeps the panel from warping, makes it easier to control the weld pool, and reduces the risk of burning through thin patches.

Long, continuous welds concentrate heat along the seam and raise the chance of distortion. Welding with maximum voltage increases heat input even more, which is the opposite of what you want when trying to minimize thermal effects. Welding from both sides with no clamps can lead to misalignment and distortion without offering any inherent heat-management benefit.