60 Gallon RF Planning....

Discussion in 'Reverse Flow' started by inkjunkie, Mar 20, 2015.

  1. inkjunkie

    inkjunkie Master of the Pit

    Picked up an air tank a week or so ago.....just your garden variety Craftsman compressor tank. Trying to figure out some of the math using the calculator that is found here....


    Some of it is pretty much a no brainer...I have not cut the tank open yet so I just plugged in the number I got from Feldons calculator which was 13860 cubic inches.

    Took that number and used x.004 to come up with 55.44 square inches to come up with the FB/CC opening.

    Took 13860x..004 again to come up with 55.44 square inches...for the area under the RF plate....

    Took 13860 X 0.004 = 55.44 square inches....area required at the end of the RF plate in square inches

    Took 13860 X 0.33 = minimum volume of the Fire Box...which is 4573.8 cubic inches....

    Is all of the above correct? Which leads me to my first of what will no doubt be a truck load of questions...which is a better firebox design....taller than wide? wider than tall? Assuming that depth is more or less a non -issue....and to a point is determined by what length of firewood will be used? This is of course keeping the length in line with keeping the FB the right size. Should the FB be no wider than OD of the tank?

    Not even going to look at the circle part of this...my head is already spinning...
  2. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    The circle part is easy...... it is a step by step that even I can follow....

    FB the width of the RF plate for easy fit up.... taller for room for ash..... longer for longer wood....
  3. inkjunkie

    inkjunkie Master of the Pit

    At what point is the FB to large? The OD of the tank is around 22". If the FB were 22wx12dx18h it would be 4752 cubic inches. According to an online calculator it would be 104% of the recommended size. A 22wx18x18 box would be 156%.
    Last edited: Mar 21, 2015
  4. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    How big do you want to build the FB..... Building it the width of the RF plate, or a bit wider, makes for easy fit up... Taller and longer are no problem...
  5. If your considering an ash pan drawer for easy clean up you'll add to the height but don't consider that extra in your math.
    I'd go with the 22x18x18 for 2 reasons, it will maintain symmetry with the tank and look better in the end. The other reason would be that I'd use the bottom 2 inches of the firebox for that ashpan drawer.
    also if I was giving advice about the ashpan, cut the drawer opening so that it will slide On the bottom of the firebox. That way if any ash misses you can just rinse the firebox with worrying about how to get the water out.
    inkjunkie likes this.
  6. inkjunkie

    inkjunkie Master of the Pit

    Thanks for the idea. Bit in the dark...hard to put my question into words, will attempt to make a sketch of what I think you mean when I get back home...Thanks again
  7. Read this build I did, it should help you with some of the things your thinking about.
    It's a quick thread so if you have any questions about specifics just ask and I'll help anywhere I can.
    just a size note, the guy I sold this build to has given me feedback and said that he fell asleep during a smoke one day and 2 hrs later was able to come out and see the smoker was so darn efficient that he just added 3 logs like nothing had happened.
  8. inkjunkie

    inkjunkie Master of the Pit

    Will take a look at it...Thanks
  9. inkjunkie

    inkjunkie Master of the Pit

    First question.....how did you secure the insulation to the firebox?
  10. I just overfilled it so that it required a little pressure to close it. The welding of the outer sheets took care of holding it in.
  11. inkjunkie

    inkjunkie Master of the Pit

  12. I am starting a small version of one that I will likely build a big brother to
    it's the same size as the build in the post I showed earlier.
  13. mad dart

    mad dart Smoke Blower

    Go after it Doug! I will be doing about the same. Tanks are hard to find around here. 
    Last edited: Mar 24, 2015
  14. inkjunkie

    inkjunkie Master of the Pit

    How's things Louis?
  15. mad dart

    mad dart Smoke Blower


    I have been studying doing mock calculations etc for my 1st RF build. Learning a whole bunch. I did find out quickly that the Feldon Calc's were off, kinda thought the FB to CC, CI calculations look pretty small on some other builds before I found it out. As you stated some of this stuff is straight forward. I am jotting down my idea of what I want from multiple builds then it will be attack mode. 

    One of my neighbors has 3 propane tanks stacked in what looks to me like a junk pile. I am going to head over there and see if I can take one off his hands. They are bigger than what I want but I would just Lopp off 1 of then ends at the weld joint and section some out. This way the door or doors don't wind up all warped from taking out a middle section and piecing it back together.

    My Tig Welder has a Stick provision as well so I may go old school on the fabrication depending on how thick the wall is that I end up with. Ahhh, maybe Tig the whole thing! Here I go again..... Lol

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