i found an awesome deal on craigslist. it's an old tank that was used for storing anti-freeze for a construction company. it's 13' long, 28" ID, 1/4" thick. i'm just curious if this thing is gonna be safe to use to build a smoker? any help would be super duper. http://amarillo.craigslist.org/for/1529325236.html called the guy and asked what the tank was used for. ad didn't tell that info.