[Kevin in NJ]

The right way is to do it on the car. You need them installed so you can insure you have the right curves so the fender bead will be inline and the back edge sitting in the right place.

Play with the fender in place to see how much it can move so you have a better understanding.

First open of the bead carefully and cut back the wire on either side.

With the fender on the body you need to bring the crack together and weld by small fully penetrating spot welds. If you have tig or a very small tip torch then you can hammer the spots each time after they cool to correct for the shrinkage from the heat. If you mig weld you must first grind the weld down smooth then hammer to correct for shrinkage.

Full penetration is critical to a good weld. You must melt the metal on the back side.

A TIG welder make this job MUCH easier. With patience you can do it with other welders.

To grind in to the bead area I like to use a Dremel tool with a fibered cut off wheel.

The last thing is to get the wire welded in place and the bead curved over.

I have metal working hints at my website.