Paul Jones says
be This is a dedicated dent pulling accessory designed to power weld studs and pull out damage using a vehicle’s existing 12 V battery rather than a mains-powered unit. In the bodyshop it’s useful for mobile work, smart repairs, or areas of the workshop where you don’t want to drag a cable welder around just to pull a few small dents.
In practice, you clamp onto the battery, adjust the power level, and use short, controlled triggers on clean bare steel. Good earthing and clean metal are critical; any paint, filler or corrosion between the earth and panel will give weak or inconsistent welds.
A common issue I see is techs not keeping the electrode sharp and pointed, and so turning the power up on the unit and subsequently producing less pulls. The LED on the unit should never need to be above two and the electrode should also be pointed. This means less surface area to weld requiring less power to do so.
If you weld for too long on the panel not only will you not get a lot of welds per charge but also you will burn away the galvanising layer to the back of the panel and so create potential rust spots.
Paul Jones, Technical Director