If you're a dab hand at silver solder, silver brazing and straight brazing, like me :-), then aluminum is no problem. Just have to keep your tip size and flame down to match the metal. But I guess not everyone has done a NASA standards course like I did back in the 70's when oxy was still the predominant method.
Oho, Ninja Welding Skillz!
Rare indeed, these days.
