I've been into smoking meats (and cheeses and other things) for years. Some of the earliest posts in this blog are about DIY electric flowerpot smokers and controllers! In addition to several of those, I've had a knock-off big green egg (pit boss brand) for a few years. It's a solid grill and a pretty good smoker too. After living in Texas for a while however, I've been building up the itch to build a "Stick burner", an offset-firebox smoker, of the kind most often associated with texas BBQ. I did a bunch of reading and watching of videos (especially Aaron Franklin's book and video series), and got a pretty good idea of what I wanted to build in my head: a smoker based on a 120 gallon propane tank, with another piece of tank for a firebox. Non-reverse-flow. There are a million articles out there that help you settle on relative size between the firebox and the cook chamber, and the size of the opening between the two, and the smokestack mounting setup, so I won't bore you with those details here, and you'll see the choices I made!
I'll start this with a note: I've been using this smoker for a little over a year now and I LOVE IT. I have only made one small change since I built it, and i thoroughly enjoy cooking awesome food on it.
Anyway, it all started off finding the tanks. In early July 2020, I found a local craigslister with 1.5 120 gal tanks for sale. I overpayed for them a bit, but it was worth it to get started! I happened to have a small ATV winch lying around, so I bolted it to my toolbox to help slide the tank up the ramps into the truck:
That's the first tank, the other one was already cut in half and in the foreground of the 2nd picture.
Cutting these things open is dangerous. I called the local fire department to see if they would come over and probe the tank with an explosive gas sensor, but they refused, citing liability. I thought that was pretty lame. In the end, I filled the whole thing with soapy water and cut it that way (I made the first cuts when the family was out of the house, just in case). It really wish the FD had helped me out, but apparently I survived.
Next up was starting the frame. I bought a bunch of square steel tubing and got started cutting it up. Making the legs slope in was great, it prevented wobbing in the front-back direction. Should have done the same left-to-right, but i ended up gussetting the corners, as you will see later, which worked fine. Yes, I use a miter saw with an abrasive blade for cutting steel. No, that is not a particularly good idea. Yes, it makes nice cuts and great angles. The welding was done mostly with my 115v lincoln MIG setup. I als used my TIG a fair amount, mostly just for practice using it.
The next challenge was figuring out how to link the cook chamber and firebox. I looked up some formulas to determine the area of the hole, but I was not at all sure how to SHAPE the hole correctly. You can see here that it's not trivial: if the domed ends were hemispheres they would intersect in a circle, but they aren't, so they intersect in some sort of ellipse-like shape. Side note: the engine crane i have was INSTRUMENTAL for this build. There's no way I could have done a lot of this without it.
I ended up taking a white crayon, cutting it to about 1.5 inches long, and sharpening both ends. I held it parallel to the ground, and dragged it around the intersection of the 2 pieces in the above picture. It left a mark everywhere that the tanks were (almost exactly) 1.5 inches apart. I did a little measuring and the hole size looked good, so away we went. Honestly I am REALLY happy with how well that worked.
Almost all of the cutting was done with my LOTOS 220v inverter plasma cutter. It was another awesome tool for this build. I cut a plate and welded it over the open end of the firebox, but I seem to not have taken any pictures of that step. The lip left at the bottom is to hold the bottom edge of an ash cleanout door. I drew on the firebox door, cut out the left edge, and then welded the beefy hinges (an amazon purchase). Welding the hinges on prior to cutting out the door lead to really good fit, you just have to be careful about lash/slop in the hinges, so the door doesn't sag when you first cut it out. Then I cut the rest of the door out and welded 1" bar along the edges to help form a seal.
I also cut out the ash cleanout opening at the bottom. Next I extended the frame to support the firebox (you can also see the triangular gussets I added to the frame to make it more rigid. these worked great)
I also decided I wanted a top door for the firebox. This allows a couple of things: 1) it's convenient access when building the fire or cleaning out the firebox. 2) it allows for searing meat directly over the fire on a removable grate. 3) it lets me put a charcoal bin in there if I decide I don't want to cook on wood for one reason or another. After a year of using it i'm SUPER glad I put this door in there, even though I still haven't built the searing rack for it...
I couldn't decide how many thermometers I wanted, so I ended up with 5. It's probably overkill, but it's nice to see how temperature varies inside (it varies a lot left to right and top to bottom, which is actually very useful once you get a feel for it, as you can cook a bunch of food that needs different temps at teh same time. Here I am adjusting the probes to they all read correctly in boiling warter at 212*F (100C), which is conveniently close to the temperature range for most smoking I do (~225-300*F). These were pretty cheap amazon thermometers, and so far I'm quite happy with them. I did manage to break one and had to replace it.
Next up was cutting the main cook chamber door (again, welded the hinges on before finishing the door cuts), and a ton of paint stripping. I started with a grinder, then switched to a chemical stripper. I should have just stayed with the grinder (outdoors). The paint on these things was a nightmare to strip off with the orange-based stripper I used (not aircraft stripper, i've had enough unpleasant experiences with that stuff to avoid it when I can). I also added some extra loops to the top of the whole thing so that I could pick the whole smoker up with the engine hoist and load leveler bar I already had. This was super useful for moving it all in and out of the garage for grinding and other processes.
Up to this point, I'd made pretty quick progress, my son Max (who was just about 4 at the time) was lots of help and enjoyed being around while I worked.
Then we had our second son (Calvin) and progress slowed down a bit ;)
Next up was the smokestack manifold. This middle-height setup was based on Aaron Franklin's design. It seems to work great.
And after that, I started working on the inside, with a grease dam, drain, and a baffle plate to reduce direct radiant heat coming in from the firebox. This was a bunch of educated wild guessing, trying to balance out radiant heat rejection with a nice free-flowing smoke path. It seems to have worked out pretty well. You can see in here that I was grinding down the inside surface as I worked, making sure that I had a decent metal surface to weld to. The dust that came out definitely also had a smell of propane (actually the odorant chemicals in the propane), so it was nice to get that out of there as well.
I didn't take as many photos while working on the inside, but here you can see the general layout. The lower (main) grate is the full size of the smoker, and fits into C channel. There's also a support in the center. There are some tabs at the left edge to hold a stainless steel water bucket. There are also upper C-channels that can each hold a half-rack, which is great for things like beans or sausages or just packing ribs in there.
Finished building the racks and got it nice and hot to burn out any leftover nastiness. Then it was time for paint. And splitting cherry. And building a little patio for the smoker...
Last step was having my neighbor Brian help me manhandle it around back to its new home
And finally, a selection of delicious smoked meats!
The only thing I've changed since I built it was to cut the firebox door horizontally between the hinges, so I can open the top and bottom independently. This helped prevent heat from escaping "the wrong direction" out of the open firebox door, and helped me burn wood more efficiently.
