Hello everybody. I'm trying to design a 5' reverse flow smoker out of 20" x1/4" pipe with the firebox cut from the same pipe at 20". I live up in the Great White North, and insulation is a must for me. So first problem that comes to mind is a shell for the insulation. I was thinking of buying a few 55gallon drums and covering the mineral wool with them. I can't imagine what the hinges could be like with a double walled door. Any suggestions for insulation and shell would be appreciated here. Next thing I would like to know about is the warming drawer. What kind of temperatures would I expect to have in there if it is directly on the fire box with only 1/4" of steel between them? Or I was thinking of having the chimney come out the side of the cc and into the warmer and exit out the top as a source of radiant heat. I have a ton of questions but not a lot of time right now so I'll ask one last thing. With a well drawn out plan and an experienced welder how long do you figure this build to take? Thanks for taking the time to read this.