I guess it was a little foolish to run such a short pipe into the smokehouse, or to build it out of wood. Anyway, you would want to modify slightly:
Here it was in all it's splendor. I finished it only the day before I destroyed it.
First I trash-picked the grill and stripped it.
I Built this cabinet a few years ago and it wasn't really doing much, so I decided it would better serve as a smokehouse.
The next step was to cut some holes for intake and the smokestack.
Here is the grill fitted with 4" black stove pipe.
On the opposite side of the pipe is the intake with a damper made from a scrap of sheet metal. Some fine work with an angle grinder by my brother.
Here is the smoker on it's first burn. You notice the large slot on the upper side of the wooden box; I left that open to see how air flows. I will be closing it and installing a proper chimney to a)keep smoke in and b)help control that temperature.
I can already tell that regulating temperature will be difficult, but I should get some good smoke flavor from it.
Here I have installed a baffle/drip pan and a steel grate (the one left from the salvaged grill,) it fits almost perfectly, and I am now ready to start smoking! I just need to get up to Cabela's and buy some mesquite logs.
Today I smoked some salmon, which requires relatively low temperatures. I used 4" logs of mesquite split in half. After building a large fire out of scrap wood and developing a bed of coals, I put one of the half logs on and closed the dampers.
Adding another 1/2 log every 30 minutes or so, I was able to maintain 140-160 degrees inside the smoke box steadily for 3 hours. The salmon came out amazing and it didn't require much wood!
Next step: 250 degrees for 5 hours!
Here is the smoker with the top section installed. The plan is to keep this section cooler than the main part for jerky and cheese.
First I drilled some 2" holes in the center drawer for ventilation.
Then I drilled holes in the old top to allow smoke to the upper section.
Here is the upper assembly with smokestack and door installed.
I cut the pipe every inch or so and flared it out, then attached to the roof with some Tek Screws.
All I still need to do is put in a drip pan!
On the first burn, I was able to maintain 220 in the bottom section and 130 in the top. This was with high winds and 40 degrees outside. Tomorrow is RIBS!