Nearly thirty (<30) years ago, I had a good-ol-boy Cajun aluminum boat & truck bumper builder do the aluminum repairs on my car; sectioned two (2) rear shrouds to make one (1) and some flange and tear repairs to the front shroud.
I can guarantee that he didn't use anything special, but he sure could handle a TIG torch! I had told him ahead of time that they were notoriously hard to weld, but he felt otherwise. I believe his name was Pat Miller, if you ever need any aluminum work down around Opelousas, LA!