Found Tank New Build

Discussion in 'Reverse Flow' started by ron petersen, Mar 10, 2013.

  1. Found a compressor tank from a customer, looking to get started. Already cut the tank stand and compressor stand off.

    Would like some ideas to what threaded inserts in tank. Will cut and fill if not needed.

    Open to ideas and suggestions.

    I have so many questions, mostly measurements, size, etc.

    thought about a few things, not sure if I am going to go trailer, then again, maybe??? Would like something that looks nice in the back yard and be able to take out to the park, lake,etc. I live in North Dakota and would like to use in the winters.

    I like "My trailer smoker build" by ryan BC

    Here is the tank: Measures 30x45, tag on tank says 113.3 gallon. Which size do I use for the calculator, both measurement and gallon size are different. Not by much, so is it better to go oversize on the firebox and stack?

    I thought about a few other items to add onto the smoker such as a hot water heater with cold water tank, burner for frying or cooking corn, rotisserie, maybe a warming box. Would like to have some other options like a propane burner for regular bbq'ing and starting the logs in firebox.

    Boom box, ice cooler, TV/DVD player.... Ok, getting little carried away.

    Anxious to get this built as weather warms up.

    To start, I have used the calculator for the measurements of the tank as it was a little larger 22x22x24 firebox. Will probably use 1/4" plate and maybe insulate it with blanket? Or use fire brick? If I go with fire brick, do I increase the firebox size to the bricks?

    What is the best size for the cut-out for the door? Would like to have 2 cooking racks.

    Sorry if too long, Thanks in advance for your help,


    Thinking of naming the smoker Fat Boy (chime in if someone else has name.)
  2. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Ron, morning...    I'm using the numbers 30 x 45 for the smoker...  the first number I calculate is the firebox to cook chamber opening...  then multiply that number by 1.5 for an estimate of the area needed under the RF plate....    Then using the arc/circle calculator I get Chord AB which is the width of the RF plate needed inside the smoker.....   I would suggest you make the firebox that width or a little wider for easy fit up...  I came up with 26" approx RF plate width.... 26" would be the first dimension of your firebox I would use....  Just makes building and fit up a lot easier....   Those numbers are the start for a "Plain Jane" Reverse Flow smoker that will be the best smoker in your area... 2 air inlets will be needed for GREAT heat and air flow control....  1 under the fire grate and 1 even with or slightly above the fire grate...  See Rib Wizzards builds.... He is the expert....    [​IMG],31.80&fi=0,0,0,37.44,0&fc=11.28,15.94,99.84
  3. Little lost on some terminology and measurments. Not good with math. Guessing when you meant multiply area needed by 1.5, assuming by 99.84? If so, then I need to set the RF plate to that volume? 149.76 sq in? Assuming plate is about 6-8" from bottom across the tank to same or bigger opening for the reverse flow?

    The firebox should be 24x20x26 according to the calculations, can I go an additional 4" (24x24x26) so I can have a cooktop? Using 1/4" plate for box. I am liking the idea of using sand as an insulator with openings to drain/replace, if needed.

    Have not found any ideas on how to make a cooktop on top of the firebox. Links anyone?

    How thick of material should the RF plate be? I have 1/4".

    How high up from the bottom of the RF plate to bottom of the door should it be? Would like to get the door measured and cut open.

    I am still lurking thru the forums getting ideas.

  4. Found a piece of 6" tube for the stack. And possible a trailer with a tank on it, was told it used to be an oxygen tank from the military. Will know more when I see it. Mainly interested in the trailer.

    Had a thougth about a burner on top of the firebox. Where there is supposed to be a baffle plate to keep the RF plate from getting a hot spot, can I make that baffle plate adjustable to where I can get more direct heat to control the "burner plate"? The baffle plate will still work to keep the RF plate from getting a hot spot.

    Any thoughts? Hope I am making sense? I am in the process of drawing the plans out, just been busy. Hopefully by this weekend.

  5. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Ron, morning..... Before you start cutting, draw up what you want and we will run the numbers... I will do a pencil drawing for clarity and things can be discussed with our knowledgeable members to make sure you build the best smoker in your neighborhood....  In my signature line are links to stuff that will help you in your build.....   Dave
  6. Here is my drawing, had to take photo by phone, scanner acting up.

    Hope it's readable, let me know what I may need to do.

    I am still having a hard time understanding the firebox to cook chamber opening.


  7. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

  8. Thanks a Million for the help. I do have a few questions.

     1. You show add plenum for good air flow which I understand well. I kinda like to use the top of the firebox as a stovetop to cook if possible. Not a big deal. If I go without plenum how low from the RF plate should the pipe go to.

     2. What slope is recommended for the RF plate for drippings, I know adding angles will add more room under the RF plate.

     3. What height should the bottom rack be from the Rf plate? And the top plate?

     4. How far in sould the firebox go into the tank?

    Might get started today.


    Last edited: Mar 17, 2013
  9. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    1...It is a toss up.... Room for a warmer or lose cooking rack space with the exhaust stack inside the smoker.... ???????????

         Using the top of the FB for cooking is good....  If you put in the 2 air inlets to the FB, it's temp will be 250 - 300 deg....

         Properly balanced FB using both openings, the heat should be removed from the FB and heating the CC...  

          Using less wood....  That is what I am told from folks that modify their smokers... FB is much cooler... Less wood burnt...

          Temps in CC easier to control.... and faster recovery....

    2...Probably one inch over the length.... I don't own an RF smoker but, it seems to me, most stuff would dry up or evaporate on

          a plate that was 250 + in temp.....  wouldn't be much to drain out.....  

    3...3-4" above the RF plate will leave more room for another food rack... Higher might give more even temps due to air flow... 

         Remember, there is radiant heat coming from the RF plate.... The entire build is compromising one thing for another....

    4...some folks build the entire FB on the outside, some say 1/3 inside the cook chamber... 1/3 inside adds heat to the RF

         plate and saves on wood....  The heat can be overcome with an additional plate mounted under the RF  plate with about 

         1/4 - 1/2" dead air space for the first 1/3 or so of the RF plate....  and some folks extend that plate to the entire top side

          of the firebox.....  that saves heat for the cooking chamber, also removes heat from any type of warming box installed above

          the FB.....

    Now you get to think of the plus and minus effects of everything you do on the smoker......  Which way to go..... lose sleep....

    pull your hair out..... have another beverage and think some more....  HAHAHAHA....  Am I helping you out here ... 

    Maybe you can find someone to tell you what the perfect smoker has,  how it's built, etc.... Not me...  every smoker

    is personal preference for the owner......

  10. jarjarchef

    jarjarchef Master of the Pit OTBS Member

    Dave is the man to run things by.....huge walth of knowledge.....

    I am in to watch [​IMG]
  11. Lots of great ideas and I am going to go with the suggestions above. I am going to go ahead and do the plenum as Dave recommended for better flow and more rack room. Hopefully will be able to go to shop today and get this started, just depends on wife. Been working too many hours.

    Thanks Dave for the help. Think I am getting another tank. Will get it and set aside for next project. Waiting on the trailer.

  12. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Ron, Run the stuff through the 2 calculators again for your reassurance and check to my numbers....  It should be fairly easy having the numbers on the page already...  and will help you understanding how the numbers work.....     Dave 
  13. Dave has you headed in the right direction.

    My thoughts on the firebox inset are this. Figure out how much you need to use as a cooking surface, add that to the distance the plenum sticks out, and stick the rest under the cook chamber. On my build almost half the firebox is under the cook chamber. It fit the trailer better that way.  It is all personal preference and what you have to work with. There is no such thing as the perfect smoker that will fit everyone's needs. Good luck and have fun with the build. I'm looking forward to seeing the progress.
  14. I am getting ready to start on the project, hopefully no more snow and hopefully not a huge mudhole at work. Don't want to spend time cleaning up a mess in shop.

    I am going with Dave's drawing. Still looking for 1/4" or 3/8" plate steel for the FB. I thought I had 1/4" plate, turned out to be 3/16". With the North Dakota winds we have, would like to try to keep the smoker from changing temps, etc.

    I am installing the FB 1/3 of the way into the tank and will add a baffle plate in FB. Found some hinges for doors for couple bucks each.

    Will get photos as I go along.
  15. Have a question, The welds on the tank are quite a ways inwards from the ends, is it ok to cut the door outside those welds to give me a wider opening?

    Don't mind grinding smooth if neeed. If I cut inside the welds, it'll be approx. 10" or so of wasted space.

    Hope this makes sense?

    Also would it be wrong to name this Fat Boy, looks like someone else got the name? Maybe I'll have another name as work progresses.


  16. bruno994

    bruno994 Master of the Pit

    I would reccommend staying inside the welds of the tank.
  17. Thanks, will keep it inside welds up to the trim.

    I am thinking if I should make the firebox a bit bigger by a few inches. Will be adding an ash pan, fire grate and a propane wood starter. I can always control the heat with dampers or if too big add some firebrick? I am getting ready to get metal cut and still looking into 3/8 plate if it's affordable. Hoping to find some in scrap pile.

    How big should I make the Plenum?

  18. Ron. This looks like fun you were gettin me goin with that first post... Maybe you should start with an RV???
  19. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Ron, morning..... A little larger than the stack on the top and larger enough to accommodate a smooth air flow to the stack...  Eyeball it... what ever you do, it will be better that cutting the stack an 45's and having a 90 deg entrance to the cooking chamber....   The idea is to not restrict the air flow to the vertical stack....  

  20. thechuck

    thechuck Smoke Blower

    Nothing wrong with that at all Ron... in fact I was thinking of changing mine from "Fat Boy" to "Chunk" (reference to Goonies and I call my 7 month old 30lb son Chunk. HA) or "Moose" (was my dad's nickname... and boy did he love bbq!). Even if I stuck with Fat Boy, it'd only bother me if you were my neighbor and built one exactly like mine... then it'd be on!

    Looking forward to your build!

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