24" x 84" Propane tank brain storm with build starting. Pics added

[p3ripperfw]

Hey guys as I mentioned in the introduction section I just bought a 24" x 84" propane tank to build a reverse flow smoker on a trailer with. I originally was going to copy a design a local builder uses but thought I would see what ideas you guys might have as well. I was originally going to just cut the tank at the 2/3 length so I would have a fire box 1/3 the size of the cook chamber. I was planning on just using the 1/3 end of the propane tank as my fire box to cut down on material Id have to purchase. Then I started seeing more designs incorporating warming cabinets which I think would be nice to have and also I figured I could use a square fire box and use the cut off end of the propane tank on end on top of the fire box for a warming chamber. I also had the idea of cutting the tank at 54" for the cook chamber and the other end of the tank to 20" for the fire box. That would give me a 111% fire box volume according to feldons. I was thinking I could use the 10" ring that would be left after cutting the tanks to these lengths and make a round santa maria style charcoal grill / disc cooker at the front of the trailer to use for burgers etc while the slow cook is going.

Looking forward to yalls insight.

For reference this was the original design I wanted to mimic with my build...

http://www.johnsonsmokers.com/patio-trailer/

[Big T]

I have a 24''x48'' that I built from a stick of pipe that looks very similar to your link. I built it using all free material so I didn't go with a square FB and warming cabinet. If money wasn't an issue I would go square with a WC but there's nothing wrong with round. There's a few options on the WC, some guys put an opening from the FB to the WC and from the CC to the WC and some don't have any openings just a vent to let heat out if the WC gets too hot. RC has a nice SM grill that he built using the bell that he cut off of a tank so that cut off should make a good one.

[Smurf]

Welcome p3. All good ideas and you have started off right by doing your research. Lot of info to found on here. After several cooks on my first smoker,24x50, I wish I would have built one just a bit bigger. Also wish I would have added a grill and fryer. A lot easier to now than later. I like the look of a square firebox but that's just me. Good luck and post pics.

[p3ripperfw]

Thanks guys.... I'm really starting to lean toward the square firebox with the cut off tank end on it for a wc. Issue I'll have to work out if I do that is configuring the firebox for the cc but it will have to be 24x24 to mate up with the wc which is 24" diameter.

[p3ripperfw]

Another thing I want to keep in check is the size..... I want the cooker to still be useable for a brisket and a couple butts if I'm just coking for the family. I don't want it so big that it takes $100 in splits every cook.

[Big T]

They're pretty efficient cookers if you build them right, I average about 2-4 splits per hour on mine depending on how full it is and the weather conditions. I think you'll be happy with the 54'' CC, it won't be a monster but it isn't too small for the bigger cookouts.

[p3ripperfw]

Sounds good big t. 54" sounds perfect to me too. I may have to make a 24x24x24 firebox with some interior dividers to cut the volume down to the proper size for the cook chamber but so that it will mate up with the 24" diameter warmer.

[Big T]

The interior dimensions are all that matters, if you are going to have false walls you could insulate the FB but that isn't really a must.

[p3ripperfw]

Good idea big t. I bet that would help a bit with fuel efficiency if I'm lucky.

[temurf]

If you go with a warming cabinent, don't use its volume while calculating the Fire box size, only use the cooking chamber volume.
When I built mine using a 15x36 tank, I screwed up by adding the volume of the WC to the volume of the CC and ended up with a firebox that was way too big. I decided to insulate the inside of the FB and now after quite a few cooks, I'm glad I did.
She is super efficient. I use a split every 45 min to 1hr.
I have openings between the FB & WC and between FB & CC with dampers on both.
She's the perfect size for the backyard, But like Smurf said, I wish I had made her a bit bigger.

Theese folks love to help so just ask. Keep us posted on your progress.

[p3ripperfw]

Thanks for the advice tenure! If I go warming cabinet I think I am going to rely on conductive heat off the top of the firebox only. I think it will be plenty. If not I can always cut a damper in later. Another question I have is on the stack. On that design I posted above they put the exhaust at grate level. With a warming cabinet this will be in the way. Should I drop my stack down into the cabinet to grate level or weld it in flush with the top?

[Gizmo]

Direct out the top will work just fine

[Rodcrafter]

Just so you know the warming cabinet can be so useful it may be the only cook chamber you use. I made mine with the opening between the FB and WC and also added a GF to the WC. It is awesome, I make jerky and cook almost everything in that cabinet.

jm2cw

[p3ripperfw]

I could definitely see that rodcrafter! I think it would be cool if it could be controlled to the point you could use it as an oven for cornbread in cast iron or keep it cool enough for keeping things warm. I dont know if that is realistic or not? I could definitely see it being a great chicken cook chamber if it could be kept hot enough.

[p3ripperfw]

What is a GF by the way? Did you put a damper on the inlet from the fire box to the warming chamber to be able to control heat and smoke coming in?

[p3ripperfw]

Direct out the top will work just fine

Are you referring to the stack gizmo? So it makes little effect having the exhaust at grate level? You always see the claim it draws the smoke down near the grate level and keep heat in the top of the chamber to help maintain the cook temp. You read a lot of different claims though so I wouldn't be surprised if it didn't have as much benefit as claimed. Lang smokers take it out the top but I couldn't see a clear picture whether it was extended down into the cook chamber or not.

[Rodcrafter]

Yes I put the FB together then added the cabinet above it with 1.5" of 2000* insulation then another plate for the bottom of the cabinet. The damper is a 6x6 square tube thru both plates. I seasoned it at 450* and can run it low enough for jerky @155* using the GF. That is a Gravity Feed. This was a grab at an all in one.





Making memories!

[Big T]

The stack debate has been going on forever but I always go straight out of the top and I've never had any issues.

[p3ripperfw]

[p3ripperfw]

Awesome build rodcrafter I like the way you think!

[p3ripperfw]

Rodcrafter what gauge plate did you use on your insulated firebox?

[Rodcrafter]

I just insulated the top so I could control the WC temperature. The FB is 3/8" and the WC is 1/4". The door and bottom and throat sides of the FB are 1/2".


Making memories!

[p3ripperfw]

Sounds good rodcrafter. Thicker dimensions than I was expecting but I can see the benefit of having the most heated areas as thick as possible.

My dimensions for the fire box are coming out to 24, 20, and 18". Keep in mind I'll be utilizing the 24" diameter by 30" tall portion of the cut off propane tank end as my warming cabinet and it will stand on end on top of the firebox with the domed end as the top with a chimney separate from the cc. I will do like you and insulate the top of the fire box and put a damper between the FB and WC.

I am thinking I will make the top of the fire box a 24" x 24" square plate. This will give me the size I need to mate up to the warming chamber but also the depth I need for the 24" dimension listed in the FBI calculator. The fire box will be 20" deep vertically. The fire box will be 18" in width.

Does that sound like the best way to meet the volume criteria of the FB and match up with the WC cylinder?

[Big T]

That's probably the best way to achieve what you are wanting to do. RC tends to build things that last forever, most guys use 1/4'' plate.

[p3ripperfw]

Sounds good bigt. I'll probably reduce some of those dimensions but I like the thicker FB bottom, door and throat idea. May go to 5/16 or 3/8 instead of 1/2".