Originally Posted by barry123400

There is a nozzle for migs that is cutaway on two sides. Or another way to look at it is it has two areas of the nozzle protruding.
So when you spot weld with it you can press the two pieces of metal together before you activate the gun. A person could modify an old nozzle as well.
One more nozzle variation is a tube welded diagonally on the side if the nozzle. You insert a steel rod until it touches the metal. Pull your trigger and it welds the protruding rod to the sheet metal. Then you can pull the dents out. Just grind the rods off when you are finished. Again with a little effort you can make your own if unavailable in your area.
Just thought I would mention as they may not be common. But what do I know. Either way they are useful and not rocket science.