I would be very leery of trying to repair a dent in a naturally finished
aluminum panel by any method (and expect very good results).
Aluminum, unlike steel, stretches significantly when bent. Thus, when one
bends the metal back, there is more metal in the damaged area (actually
longer and thinner than the original) thus producing a new defect. That is
why Airstream exterior panel repairs are typically done by replacing the
panel.
There are techniques to shrink the metal in the area of the damage, but this
disfigures the surface (which could be hidden by body filler and paint - but
not polished and clearcoated).
Oliver Filippi