An ugly mother BMW station with a trailer *** (not even round) stabbed my back door and made a deep cut in the way in and got it bigger on its way out. Being used to accidents (being a co-owner of a body shop garage) i did not panic and believed nothing is difficult to fix. However while heating the wound in order to bring it back to its form, I realized that the body is not being warmed and someone shouted ... stop it it is aluminum ! what? pure aluminum and nothing can be done. The door needs to be changed and that is as simple as it gets. Fortunately the insurance paid for the new door (actually used). I always knew that aluminum was used but not on the outside. Audis are made of aluminum from the inside while the outside rap is rich in steel so that it could be fixed the conventional way. learned my lesson well the hard way.

 

This is nonsense. Paintless dent removal can be done on aluminum bodies, although it does take a little more time as aluminum does not have "memory" (i.e., won't snap back into place).

 

on this nonsense

 

I am obviously not talking about dent and small scratches. One can get his fist in my door and it is all chewed. Heating it did not help at all (as aluminum has no memory as very well put) and more importantly welding means nothing to it.

 

you cant fix a hole by heating up the metal! That wouldn't even work on a steel car!

 

when you have a hole the metal has entered inside the body with the impact. |That quantity of metal needs to come back outside so that the missing part is minimized before filling it. That process needs to be done by heat. Steel reacts like magic and you could see it take the old shape, while heat means nothing to aluminum.

 

Maybe you can just put a TV in the hole in the door, solve two of your problems at once.

YouTube - T.V's in da fender

 

You certainly can weld aluminium using a TIG welder, there are actually two welds in the X350 about 1/3 of the way down the D-post left and right of the rear screen. Jaguar actually recruited a left-handed welder for one side, (don't ask me which one !!). However paintwork problems at the weld location caused them to develop the new X351 XJ with no welds at all.

Gas tungsten arc welding - Wikipedia, the free encyclopedia

Only problem with welding aluminium is the unpredictability of the aluminium joint strength-wise, so it is never used in airframes, only rivets, the same reason the X350 is virtually all riveted and glued together using aerospace glues.

 

Welding aluminum is not the acyual problem because as you said Gas tungstern and other methods are also common, but the true problem is to brig back the shape of the body the same as it was. With steel you heat the squashed area and you see it pop up again to its original shape (sometimes you need to help it with your hammer) but heat does 90% of the job. With aluminum we could certainly find a way to put it together (glue it together if you wish) but to bring it back to its shape is impossible. Aluminum has no shape memory. When and if welded you need to bring back the shape using tools and that requires the skills of a real artist to figure out the shape (usually by copying the intact opposite part). In the case of a deep hole we need to heat it to convert the inverted peace of steel/aluminum then to fill the remaining gap (minimum poissible). In my case I have changed the door but will certainly keep on practicing on the old one to see if I can fix it might send pictures (before and after)