A car was in a collision and the front bumper is dented inward and cracked, I'm guessing up to an inch wide. Is there a way to either fill the crack with some type of foam? (Sophisticated tools and workbench are not currently available) If not, then how to at least seal the damage with something that will prevent rust? I've seen a couple videos that mentioned primer. Is it as simple as just spraying primer on the affected area? It's an older vehicle so it doesn't have to look visually pleasing as much as it just has to protect against the elements.