I recently started using the p15 products, two thumbs up so far. I would reiterate what everyone else just said, take tiime, prep, etc. And wear gloves! I used it on some parts that were pretty rusted, even filled holes with it.....so far, so good. I was contemplating cutting out and replacing the rusted out section below the rear window on 64. Used p15, built it up, filled holes w/multiple layers and is working fine so far. I don't have a decent welder or the $ to have it done, so this was a good option for me. My only regret so far is that I wish I had used it when I redid my front suspension on 66 last year. I would have used it everywhere instead of Rustoleum!