I have a masonry offset wood burning smoker. I recently upgraded it (new doors, top and chimney) with a new chimney made of double-walled water heater vent pipe.
I was just reading through some old posts on wood burning techniques and ran across this: "The suggestion to stop using the water heater vent is a good one...the last thing you want to do is start a chimney fire in a water heater vent, (it's a vent not a smokestack) and burn down your house..."
The chimney is made of a one foot long section of 4" 1/4"-walled steel pipe, and then the 4" double-walled water heater vent pipe. Seems to me that the double-walled water heater vent pipe is a good idea. Is there something I'm not aware of? FWIW, no wooden structures are anywhere near my smoker - all aluminum.
Terry near Tampa Bay, Florida
Here's a few pics: