sealing

I just assembled a wide-body DynaGlo offset smoker, and I'm trying to figure out what sealant I should use. I figure I may need to seal up the outside of the firebox and smoke chamber, as well as the connection point of those two. Here's my two-part question: can I use the same sealant on both...

We used to roll the edge of the bag over to try to keep it clean, but it always seemed to distort the end of the bag. And half the time it still got some juice or meat on it anyway. I don't know how we came up with this method, but it works for everything as long as it will fit on a paper plate...