I've seen a display for that stuff where they sprayed it on thin gauge sheet metal and you could bend the metal to see the flex without it breaking. I don't remember if it was at a car show, or a 4x4 shop, but it looked pretty good to me. My body guy is using it on the inside of my firewall, in my cowl, trunk, floors etc to keep the rust away. He swears by it and uses it all the time when he replaces panels.