There is always the "thread the stud and twist it out" methode. Even if it spals a little, it will still come out.
Die cut the stud half way with a nut size that you can get a grade 8 nut. Thread the nut on and continue to turn once the reads have run out. Put a small amount of pressure on the nut and wrench and walk the stud out.
The dangers are the stud will not turn and will break.
Another one would be to center drill the stud and tap it out. Install a bolt and work it from there.
Problem with welding is Aluminum absorbs heat faster than steel and melts.
Just my $0.02 worth and another suggestion.
