[Zeke]

JB weld is used commonly on cast iron machined parts. On an edge it is a good idea to drill in some wire stakes. 2 things I will caution, don't start a stress runner with a drill hole for a stake and don't heat enough to alter the heat treating.

To get a puddle started on a large object, even at the edge, requires some preheating so I'd bring the wheel up to 500º in an oven, blanket it and weld the missing area in small passes using low heat. I can see why a spool gun is not suitable. Too much heat too soon and too fast of cooling.

While welding is best, JB might do what you need if the tire mounting guy doesn't start right on your repair. The zinc stuff is not strong at all and the bond is very weak. Used on many die casting repairs of zinc die-casting alloy, it offers a very low melting point, but not AL.