Check out panelbeating aluminium on google or some search engine.
Different altogether from doing steel.
*You cant really shrink back aluminium.*
It will keep streching on you.
(dont work on it when its cold,
a little heat/warmth is an advantage, not much heat!)
The hammer & dollies used to work aluminium are very different in the surface ridges.
If you work the panel too much you harden it.
george