Eh,thats typical!..bet my trucks roof has twice that thickness on it,and its cracking off in chunks!..

..I'm tempted to just put a whole sheet of metal pver it and screw it down,rather than fix it "right",the roof is rusty under the bondo,you'd have to cut the roof right off and transplant one to do it properly..aint worth it!..
Bondo used to be cheap,you could buy a gallon of it for less that 8 bucks in the 80's,the stuff with fiberglass or tiger-hair was a bit more,like 12.99-one store I worked in sold 5 gallon pails of regular bondo for 24.95 then!...-so people who weren't skilled at using a dent puller or dollys and hammers just filled dents with as much as it took to fill them,they would drill or punch holes in the panel so the bondo would ooze thru it and stay on better..
...today at 20 bucks a gallon for the cheapest bondo,it'd be cheaper to pull the dent or replace the panel than use bondo probably...my roof would need at least 100 bucks worth!..Bondo does have one advantage,once you build part of a truck out of it,that area never rusts again..
