What is commonly used for the exhaust stack

[smaloof]

What is a good material/source for the exhaust stack?

Do most people use pipe and if so what thickness is recommended? 

I ran my numbers and I am planning on having either 6 or 7 inch inner diameter stack:

               If 7 inch is used my exhaust stack will be 31.0 inches long

               If 6 inch is used my exhaust stack will be 42.2 inches long

 

[smokejumper]

Yep, pipe is the way to go. Thickness close to what you used for the cook chamber.