How To Replicate Factory Spot Welds With Your MIG Welder

We often say restoring a vehicle involves more than just taking it apart and putting it back together. A true restoration often requires meticulous attention to detail. Replicating the appearance of factory spot welds when replacing body panels is one such detail. But what if you don’t have a proper spot welder? A standard MIG welder can provide an affordable alternative without compromising on the desired vintage look.

The signature look of a factory spot weld is created when two pieces of sheet metal are pinched between the electrodes of an electric spot welder. When current is applied to the pinch point, resistance between the two pieces generates intense heat that melts them together. This all happens fast on the assembly line. Once the weld joints cool, there are typically small, shallow depressions from the clamping pressure at the electrodes.

An experienced welder can get the same effect with MIG torch and a steady hand. But for those who don’t regularly weld sheet metal (or never have), there’s a convenient kit that makes the process easy enough for almost anyone. Eastwood’s MIG Spot Weld Kit consists of three components: a pair of sport weld drill bits, a pair of spot weld pliers, and a special spot weld tip for the welder. 

The kit is deigned specifically for welding 18- and 20-gauge sheet metal. The drill bits can be used to drill out old spot welds or to create the perfect-sized hole for new welds. The pliers feature unique tangs to hold two panels together while providing an adequate opening for the welding tip. The Tweco-style welding tip incorporates two standoff posts that set the correct depth and provide stability for an ideal weld. Here’s how to use this kit.

Prepare your metal

Before welding, drill all your holes on one of the sheet metal panels. De-burr if necessary and prep with a low-VOC solvent to remove any contaminants. You may also choose to apply weld-through primer to both welding surfaces if you’re concerned about corrosion forming between them.

Align your panels

Get your panels lined up for welding and secure them in place with C-clamps, screws, or tack welds as necessary. Once in place, center the spot weld pliers over the first hole to be welded. Clamp the pilers in place to create a tight closure between the two panels.

Weld the joint

With the spot welding tip installed on your MIG torch, position the tip over the clamped hole. The welding wire should be trimmed flush with the end of the tip. Confirm the MIG welder is set for the correct amperage and wire feed for your material. If your machine has a “tack” mode, you may wish to use that for short, controlled pulses. When ready, pull the trigger on the torch and weld the open hole, making a quick circular pass to ensure good fill.

Check your work and move on

Let the weld cool briefly before confirming you have a good joint. Ideally you’ve created a shallow puddle with good penetration that looks like the factory welds. If you’re satisfied, move the clamp to the next hole and continue on. You may also wish to work in a leapfrog fashion, skipping every other hole to prevent heat buildup. 

It may take a little practice to figure out the perfect duration to achieve the correct low spot on your welds. The result will speak for themselves, however, especially in a judged concours environment. Regardless, you’ll end up with a clean, solid weld joint that you can always be proud of, even if you’re the only one who notices.