WIP- My next build.. Stainless keg RF

Discussion in 'Reverse Flow' started by biggqwesty, Sep 17, 2014.

  1. So after my keg vertical build I'm looking into ways if up grading.
    So I have a full size keg (roughly 16" D by 25" long) and can get a half keg? Roughly have the size of the full one.
    So I'm planning a reverse flow, traditional setup and I have a good grasp on what's needed..
    One thing I am worried about is can the fb be too big?? At nearly half the capacity of the smoking chamber is it to big and is there any downfalls to a bigger fb??

    This will be a slow build. Expect the half keg to be atleast a month away still..
    But will keep in touch
  2. oldschoolbbq

    oldschoolbbq Smoking Guru OTBS Member

    I have no response to the Keg thingy , however , I will be watching . . .[​IMG].

    Have fun and . . .
  3. So after getting the larger keg I've decided that one keg is probably on the smaller side.
    And noticing the mostvthe calcs call for a FB 1/3 the size of the cook chamber I'm grabbing a second full size keg.
    What I'll do is cut one around the top 1/3 and the other around the bottom 1/3.
    Then join the 2 larger peices together and the 2 smaller peices together.
    So I'll end up with one big keg and a small keg.
    Then the build. This will be 100% stainless steel. And is going on a trolley.
    Hopefully I can start this weekend..
  4. brimcconnell

    brimcconnell Fire Starter

    I'm intrigued. Will be watching. [​IMG]
  5. So I got a start today.
    This will be a 3 keg build now.
    According to the calc my fire box is over size (didn't need the calc to figure that one) ..
    So the chamber will be 15.5" diameter and 28.5" long.
    Thinking 2 doors on it with top hinges.
    The FB 15.5" diameter and 17" long. Calc recommends around 14" long. But that is just getting to unusable for long cooks.
    So I've started the cook chamber.
    More to come tomorrow hopefully
  6. dirtsailor2003

    dirtsailor2003 Smoking Guru OTBS Member

    I like beer, beer comes in kegs, so I best watch this build!
  7. Yea dirtsailor it felt wrong cutting into the carrier of liquid gold. But I think the end product will be worth it.
    So I've welded them together and boy is this a KEG!!! Imo how they should come lol..

    Now also if you have a stick welder this sorta work is within your capacity.
    I'm running satincraft rods. Not cheap but beautiful to weld with.
    I could run my tig but I can't justify the gas to purge this job so the stick it is.
    I'm running a 1mm root gap, and 43-45 amp on dc -.
    So I'm hoping that I have a nice internal seam weld aswell. But touch ups can be done by tig once doors are cut.

    So next up is the doors. Will grab hinges and some flat stainless for the door seal during the week.
    Stay tuned.
  8. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Nice weld.... You are not a beginner.... I can see that......
  9. Thanks Dave. Yea i'm a boilermaker by trade. Lol.
  10. So a little more progress this arvo.
    I didn't like the stick finish so ground it back and tig'd it..

    I also found some flat stainless so Next up was the door.
    I marked out a 1/3 door for top hinge. I then cut the sides and formed some 30x2.5 stainless to the circumference and tacked it on.

    I then cut along the top and bottom to fully remove the peice and cleaned it all up ready for the finishing flat bar but have run out. So untill tomorrow.
  11. So I'm getting back into it.
    Here are the feldons calcs.

    Link to BBQ Pit Calculator

    The only thing I'm worried about is the fire box to cooker opening.
    It says 21.13 square inch. I've calculated mine to be just under 24 square inch.
    Will this be fine or should I try for 26 + square inch opening??
  12. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Are you planning on a reverse flow.... Stack at the same end as the Firebox... If you are, try to get close to 30" at the opening, under the RF plate and at the end of the RF plate.....
  13. Yes I am planning a reverse flow. I'll try my best.
  14. Just wondering as to why you surest 9 square inches bigger? I read that the calc has some floors but is the 30 to be cautious?
    I can easily get it I think.
  15. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    The concept for the changes is below.... Alien and his associates, did an amazing job putting the original calculator together... 100% of my numbers are based on his original numbers... small changes were made for the improvements due to design changes in smokers.....
    The original measurements were taken from SFB smokers with tuning plates I do believe.... The advent of the RF smoker did not make any changes to the calculator... Now the exhaust has to travel twice as far as before, and the original FB/CC opening restricted the air flow from the FB, causing the FB to over heat... Some would get up to 450 deg and higher while the CC wouldn't get over 250.... And then there is the increased friction from the steel.... When using natural draft, any restriction/friction is very detrimental to the flow....
    So, on a whim, the FB/CC opening was enlarged, the area under the RF plate was increased and the area at the end of the RF plate was increased... all by 50%.... That solved ALL the problems.... fuel consumption was reduced.... folks were happy....
    I personally experienced members improvements and fuel usage by the letters/PMs they wrote me on their improvements...... One additional modification was suggested.... members here, tested a second air inlet to the FB.... directly across from the FB/CC opening... That was a significant improvement of some/most smokers.... If the FB was too hot, it could be cooled by opening the upper air inlet.... Also, the fire had a separate air inlet to adjust it's heat output.... It should be installed at or below the wood fire grate....
    All of this has been tested and proven by members building smoker on this forum.... The only place you will find using these numbers... or it used to be... I'm sure many builders are now using these ideas for their builds.... this process has been going for at least 2 years....
    Last edited: Nov 11, 2014
  16. Cool. That makes sense.
    Ok so 30ci it is..

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