hmm,well then,as long as the metal is clean,you should not weld it properly,why spend money on bondo?maybe you could use a quality duct tape over the holes,and then paint thick, several layers over the repair. sorry did i say all that ..really if the fit of the quarters are nice and the holes are repairable,just weld them up with patches, remove the bad metal and put new in.or you could get a new lower section.just dont bondo it.