Many(most) of my models are of ZAMAK, an alloy of zinc, aluminium, magnesium, and copper. Called "white metal" in the industry. It can be soldered, but is difficult under ideal conditions. Enough aluminium content to eliminate use of tin/lead solder. Most of my work is small where there's not a lot of stress on a joint.
There are "aluminium welding" alloys available. But they are actually an aluminium compatible solder. They will stick two pieces together but are no stronger than soft (tin/lead) solder. To my knowledge, there is nothing like hard solder(brazing) for aluminium. Beyond common "glues" there is nothing like TIG welding for larger work.
I usually use a thick type of ACC, alpha-cyanoacrylic, or "super glue". In the past, before ACC, I have used epoxy, contact cement, and "Goodyear Pliobond". There are other cements, some now obsolete, that are acetate(?) based. Those did well but after a few years they dry out and don't hold any more. JB Weld is just a metal filled epoxy. When used properly, it is no stronger than Wally World Hobbypoxy. But great for filling blemishes on machine cases. I have built machine parts from aluminium. In every case, they were fastened together with machine screws. Nothing I use will hold up as a repair to a "mag" wheel on an automobile. That would have to be welded.
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