I got the rear fender blues too,and going to try the aluminum stiffeners with the truck bed liner thing...I think about six or seven coats should do it? any suggestions....(I use to work in the oilfields of south Texas,there was a term that may come in handy about now....."plug and abandon."
I got the number to Hallaburttion concrete if you need it? L.O.L. Look in the tech.articles about the rear fender wag.a.k.a. body/sheet metal.