Need advice on small RF build dimensions (finished pictures added)

Discussion in 'Reverse Flow' started by austinb, Jun 22, 2012.

  1. ----update---- pictures of the finished smoker at the bottom

    Hey everyone,

    I'm new to the site, found it while looking around to find some ideas for a build I'm planning.  Lots of great info on here and I'm hoping I can pick some of your brains about my build.

    I have this nice tank that is 24" in diameter and I plan on trimming it down to be around 36" wide in total. I don't want the thing to be too huge and I feel like this size would be big enough but not too big.  Unless there is some reason to go bigger that I am unaware of.


    Here is a rough drawing of what I'd like to do:


    So first off what do you guys think of having the firebox detached like this?  My thinking is the cooking chamber would get alot less direct heat this way than with the attached style.  I would add some bracing not pictured.

    I have two options on the picture for the smoke stack.  Is the exit on the end better than one on the top for any reason?  Then how far from the top of the cooking chamber should the exit be (dimension D in picture)?

    Then how high from the bottom of the smoker should the drip pan be (dimension A) and how far from the end should the smoke opening be (dimension C)? 

    Finally how high should the cooking grid be off of the drip pan (dimension B)?  I plan on having a removable tray that I could put in on top of the drip pan for charcoal and use the cooker as a grill when I want to, so I imagine I may want the cooking grid to be higher off the drip pan if it it wont hurt smoking performance.

    Any feedback is greatly appreciated! 
    Last edited: Dec 9, 2014
  2. darbinco

    darbinco Fire Starter

    This link should help you with all your required diamentions, firebox size, opening from FB to cooking chamber, FB vent sizes, stack size and length.

    I wouldn't hesitate to make it bigger. My tank is 20"x60" long and after cutting the door in it, I wouldn't want it much smaller. It will allow me to smoke a brisket some chickens and ribs all at the same time. With 36" a good sized brisket going to eat up that space in a hurry and not leave enough left for anything else. Good luck and keep us posted on your progress!
  3. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Austin, evening and welcome to the forum..... please fill in where you are from, on your profile, so we can better help you when the need arises...
    edited changes
    Last edited: Jun 25, 2012
  4. Thanks for the reply Dave!

    I've been playing around with the calculator and think I've got most of the dimensions figured out.  A couple questions about your reply:

    Is having the increased heat from the firebox being attached to the smoke chamber a benefit?  I know too much direct heat can be a bad thing.

    Do you have any input on the two smoke outlet options?  Is exiting out the top better/worse than exiting out the end?

    When you say '1.5 to 2 times the size of the firebox opening', is that the total cubic inchs of the opening?

  5. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Austin, morning....  The recommendation from the calculator are pretty much time proven for building a smoker that works very well... Of course they can be adjusted for personal design differences... Most folks build to the proven design characteristics.....  Dave
    Last edited: Jun 26, 2012
  6. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member


    Squib found it necessary to install a "deflector plate" in his smoker to reduce the heat on the top of the firebox and "get the heat and smoke moving" in the right direction....    Dave
  7. So its been awhile but I've been working on my firebox a bit in my spare time and have it about finished up, thought I would post up some pictures to share. 

    The main body was made out of a 16" pipe (1/4" wall) that was 20" long.  I cut the pipe in half and welded in two pieces of steel (3/8") that were 8x20" to get my firebox volume up to 1/3rd the area of my cooking chamber.  The front and rear plates are both 3/8" so the whole thing is quite a tank, weighing in at just over 200 pounds haha.  I purchased the hinge from a local welding shop and fabbed up a simple latch.  I've very happy with how the door seal came out, I made it from some 1/8x1" flat strap and a bigger plate I cut to fit the curve along the bottom. 

    The vents ended up being a bit larger than I planned but I may go back and make the openings in the outside plate a bit smaller.  Currently with the outer plate covering up as much of the inner one as possible there is still some open space air could get in, not sure if this would be a problem when cooking or not.

    Anyway hopefully I'll get started on the cooking chamber soon.  Going to cut the hole in the firebox once its attached.

  8. Finally finished up this beast, figured I would post some pictures of the build and finished product. Have cooked ribs, pulled pork and a turkey on it, seems to work great.


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