Denny, the stuff I'm talking about is for automotive applications and I get it at my local auto parts store. It's called Rubberized Asphalt Undercoating. Giving you a brand name won't do you any good because the stuff I buy is Canadian (I can't remember the name off hand), but if you ask at your local store I think they should have an idea...
Goes on thick and stays flexible, works really good.
