quarter panel replace ment

my only problem with butt-welding..is that unless you leave some weld on the back side.. that seam, once you grind it down, is super weak. either that, or you leave some of the weld on the front, and pound it down and pave over it with filler. i would rather have extra strength, and prime the crap out of the flange, than have a weak spot in the middle of a panel. my neighbor butt-welded a set of 1/4 s on his 69 camaro. car had about 400 hp. he cracked that seam on both sides the first time that car hooked up. this guy isn t an idiot either. he s been welding a long time. i still butt-weld. i butt welded in my inner fender halves. but there is a lot of rigidity there.