DIY Reverse Flow Horizontal and Vertical Smoker Combo

[sfarbic]

Hey everyone, I have been dreaming about building my own smoker for years now. I recently acquired (3) 30" diameter diesel tanks. One tank is 48" long and the other two are 36" long. I've read many threads online about all sorts of considerations like offset vs reverse flow, firebox size, flue size, etc. I think I have a solid idea of how I want to use the tanks so I've built a 3D model in Sketchup. See PDF below. The 4'-0" tank will be my main horizontal reverse flow cook chamber. One of the 3'-0" tanks will be my vertical smoker/warming box. The final 3'-0" tank will be cut in half and used as the firebox and transitional piece between the horizontal and vertical smokers. I wanted flexibility with this smoker so I can smoker with just the horizontal or just the vertical or both. I will install a damper between the horizontal and vertical chambers which when open, will let smoke travel from the horizontal chamber directly into the vertical chamber. I will also build a damper between the firebox and vertical chamber so I can let smoke/heat directly into the vertical chamber without having it go through the horizontal chamber. My hope is that I will be able to use this smoker with both chambers going for large parties and use one chamber for smaller gatherings. I've included several pictures below to illustrate my plan. I wanted to post my plan and get some feed back from BBQ enthusiasts before proceeding with the build. Please let me know what you think.

[Jfrosty27]

I know nothing about engineering or building smokers. Or anything for that matter. Heck I was a salesman all my adult life. But man that thing sure looks cool! I hope you build it. Can’t wait to see it if you do. Good luck!

[bbqLuv]

Have fun under the sun.
keep us posted on your progress. Thank you

[Bkhuna]

Cool idea. Hope you can pull it off. Maybe have a contest on the Pit to give it an appropriate name?

[sfarbic]

Thanks for the idea about naming the pit. When I start posting build pics, I'll pitch the idea to the pit.

[RonB]

I can't help, but you might want to put sides on your wood stand in the firebox to keep the fire where you want it. At least two people here do build smokers and might be of some help:

Henrik
Ahumadora​​​​​​​

[sfarbic]

Thanks for the idea. I'll probably put some short sides on the log rack or I might make a V shaped one.

[Henrik]

That is a big smoker! The pdf’s really help 👍

I have a few questions to better understand what you’re aiming for.

1. Have you built smokers before?
2. Will you be doing the work (cutting/welding) or someone else?
3. Why have both a horizontal and a vertical, as opposed to "just" one long horizontal? I.e. what is your reasoning for that design choice?
4. And a technical question: on the 2nd last picture there are two rectangular vents on the vertical section, what are they for?

[Henrik]

Thanks sfarbic, great answers, and very good points! I look forward to seeing build photos. Let me review again and see if I can offer any advice. If not, I'd be very happy just cheering on from the bleacher!!

[sfarbic]

Thanks Henrik! I appreciate you taking the time to review my design.

[Bad Hat BBQ]

Klose and Pitts by JJ have models with a cabinet at the end of a horizontal chamber, I liked the design nad would think you could cold smoke or at least be good for cheese

I love the drawings Huge capacity!

[ILMsmoke]

I give you a gold star for being original! I've seen plenty of smokers, but never this. If you build it I hope it's amazing, but I have an opinion that's worth nothing. I live in the camp of "do one thing very well or do two half ass". I don't think your efforts would be "half ass", but I think the cookers ability could end up doing neither of its intended purposes very well. I think you could build a great horizontal or a great vertical, but the chances of mixing the two and not making functionality sacrifices are low.

[ILMsmoke]

I’m 100% rooting for it to work to perfection! You gotta take risks to get great rewards!

[sfarbic]

Thanks ILMsmoke. I'll make sure to post progress photos as I dive into it!

[ILMsmoke]

You’re getting some good feedback on here from people that know how to build a pit. Listen to them, not me. I have started my first offset smoker build, but due to major hernia surgery I'm down for a bit. I am a decently proficient welder/fabricator and hopefully will have a decent end product.

[Henrik]

Ok, have spent some more time to look at the PDFs. Here are some questions/ideas/comments:

1. the rear legs (right next to the fire box) aren’t needed, since it looks like the bottom shelf is welded to the firebox. But I can see them needed for symmetry/design.

2. the smoke stack for the reverse flow (horizontal) is too long in my opinion, I would shorten it by at least 30-40%.

3. There seems to be 2 vents on the firebox door. One small at the top, and a larger further down. Why two? Why not skip the top one?

4. I still don’t get having two vents on the vertical. If it gets too hot, just close the opening between firebox and vertical a bit, or let the fire die down a bit. Or just open the door a little.

Ok, that’s what I can think of right now. I’m not trying to critique your build in any way, I think it’s a cool project, it’s just the engineer in me enjoying constructive arguments back and forth to optimize the end product.

[sfarbic]

I appreciate your constructive questioning. Engaging in truthful dialog is how we grow. My goal is to get questions and criticisms to help me dial in my design. Keep them coming!

[Henrik]

Cool. As for no 2: yes, there is such a thing as too clean burn -> no smoke flavor.
3. With all due respect, I would like to see that work in real life. More fresh air in -> hotter fire. Plus hot air rises, cool air drops. I’d much rather just pull a log out if temps run away on me that bad. Or choke it with vents.
4. Yes, got it. Now get started building it 👌😄

[Ahumadora]

sfarbic. Understand that some of these guys have only built a few pits and the numbers you find on those online calculators are only taken off a few home built pits. I agree with everything Hank said. The upper /lower vents on the firebox don't work. Believe me I tried doing that. Lots of "experts" out there with very little real world experience.

[Bob's BBQ]

That looks awesome. Building mine was one of my favorite projects of all time. Can't wait to see pictures of the project!

[hoovarmin]

You are clearly a badass to even consider such a project. Keep this thread going with pics, please. I'm going to make some popcorn.

[MsTwiggy]

Nice sketchup model! Having a 3D model really helps visualize how everything will come together. This is a great project for you to test your hypothesis and tinker. If you don't need all the vents you can leave them shut. I think at your tier, with this project, you are going to have to satisfy your own curiosity. Good luck and full steam ahead!!! 🛤🚂 🔥🔥🔥

[glitchy]

First, this looks awesome. Second, I’m not a log slinger…though I recently bought a KBQ. The Traeger equivalent to a stick burner (just to keep Spinaker in check).

With the disclaimer I have minimal experience with an offset (like a couple cooks), have you considered an air gap between the firebox and vertical. I would think it would help let you control the temps better in the vertical via airflow through it. I’m guessing you have already considered, but wanted to toss it out there just in case you haven’t.

[sfarbic]

I have not considered it yet. I will think about that one a bit. Thanks for the suggestion.

[Ahumadora]

Stack size can be narrowed down, by how you like to cook. A smaller thinner stack is better at lower temps and a larger is better for hot n fast. I much prefer a round traditional firebox to a square. They just work and flow better. Design also comes down to what materials and tools you have available. Don't try to re invent the wheel on your first pit. Keep it simple and pay extra attention to making sure all the doors seal perfectly .

[DogFaced PonySoldier]

Very interesting, and I can't wait to see build progress pics!

I'm not a stickburner type, so my question comes only from watching people cook on YouTube, etc.

A lot of folks have a shelf on top of their firebox or something to allow wood splits to 'preheat' and sit in a staging area. Kind of an 'on deck' spot, so when they get tossed into the firebox, there is more instant complete combustion and less dirty smoke as they get started. I don't see anywhere to do anything like this - but I don't know that it's strictly necessary, but I've seen this become more of a trend (maybe a fad?) when watching guys on YouTube like Chef Tom from ATBBQ and Jeremy Yoder, etc.

Thoughts?

[sfarbic]

I have also seen videos of people preheating wood and I think the concept has merit. My firebox is large enough to put logs along the sides of the log rack so I will try this method for myself once the pit is built.