Chemical bonding of metal was required in the Lockheed L1011 aircraft (and probably everything newer than that), and there is no reason to assume it won't work on auto steel.

My only concern would be fill strength -- is the stuff as hard and strong as it needs to be if there is a large, irregular gap rather than just a thin space between the sheets.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!