liquid goop
Hi, is it an aluminum filled epoxy? Probably, I have used devcon steel filled epoxy, it is much like jb weld. I remember looking at devcon's literature and they had epoxies filled with all sorts of different metals, stainless steel, titanium, and some others. I think maybe their jb weld equivalent was called liquid steel but in a larger package the same product was called steel putty.
JB weld may do the trick for you, it is durable stuff and I think it would take the heat ok. Sometimes it helps to warm it with a hairdryer, makes it thinner and thus will seep into crevices, also heat will speed up the cure. I have used it with bits of fiberglass cloth with excellent results.
However, I think the radiator trade uses some sort of glue to effect aluminum radiator repairs, maybe look there.
good luck, let us know what you discover
Jay