Need Help... New RF to build!

Discussion in 'Reverse Flow' started by weekend warrior, Jan 29, 2015.

  1. I copied part of my introduction to give everyone a little background.

    I have been smoking food for about 6 years. I started with and still have my Green Mountain Grill. I wanted something a little bigger a few years later to process all of my deer meat (sticks, muscle jerky, sausage, and bacon) but also be able to do larger cooks. I ended getting and 1950’s Hotpoint refrigerator that I converted into a smoker (smoke daddy for smoke source, electric heating element, and digital controller).

    I like my fridge smoker, but it doesn’t produce the finished product that I would like. Don’t get me wrong it tastes good and I get great reviews, but know it can be much better. I will continue to use my fridge for all of my deer meat, but I plan on getting a RF made by a local guy that has made a lot of smokers. I would do it myself but do not have the time, tools, or skills to do the job.  I met with him and he looked at one he built about 10 years ago. It looked great but he said we could customize it however we wanted (he said there were things he would change even if I wanted the same one).

    I am attaching a few pictures of the one he made 10 years ago as well as a drawing that I made but looks like a 4 year old created with its dimensions. The dimensions shown represent the current smoker he has outside.

    So here is what I want to accomplish…

    • Reverse Flow

    • Hold up to 10 pork butts or pull out the top rack and do a small/med pig/hog. (At least 4 or more times a year I get asked to cook for graduations and parties).

    • Possibly be on a trailer (My wife’s idea)[​IMG]
    Changes to make to his current design…

    • Make it 8” deeper

    • Make it 10” taller

    • Make it 10” wider

    • Increase fire box size if needed


    • The distance between the bottom rack and bottom plate is only one inch. I think it should be at least 3 inches from what I have read on here? That is part of the reason for the 10” increase in height (some of those inches would allow for a larger gap).

    • The dual stacks are 3ft tall. Does that sound about right?

    • The grates he made at the time were stainless steel. I was thinking more along the lines of expanded steel, and he agreed?

    • The firebox has 2 openings with a slider. When wide opening each opening is 3.75”x 7.5”. Does that sound about right?

    • What about the drippings? Do you just let them fall onto the bottom plate, or build in some sort of drain?
    What would you do to improve upon this design?

    What am I missing?

    The gentleman building this told me to put together some designs, and was happy to work with and make whatever I wanted.

    Any help would be appreciated!!!

  2. Based on my calculations the current setup has approximately 9054 cu/in of space and if I increased the size I would go to 9854 cu/in (may be off a little). My wife thinks I am crazy because I told her to keep all of the cardboard in the garage so I can build the cooking chamber to scale so I can see how big it is.

    The calculator says my fire box should be 3311 cu/in as opposed to the 5600 that is currently on his setup.

    I am not sure how dual stacks are to be put into the calculator, or maybe I don't want dual stacks?
  3. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    weekend warrior likes this.
  4. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Increased friction.... as I call it is when the surface area increases as the volume does not....  same volume.... more surface area...... more friction...   these convection driven smoker can't live with friction..... they won't draw.......
    weekend warrior likes this.
  5. Well I was wanting some feedback on design. This won't be a typical drum smoker (round). My computer is down so instead of using photoshop I am stuck with paint. The guy making my smokers previous design had a flat bottom (I showed this in the drawing on my first post). I was thinking about dropping the bottom down a little. Does anyone think option A or B would better than the other? Sorry it's not to scale!


  6. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Either of those designs has a VERY high surface area to volume ratio...  LOTS of friction...
  7. So is that good or bad?
  8. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

      Bad....  poor air flow...  it needs to be "designed out" of the smoker....
  9. Got it!! Need a bigger intake!
  10. How much distance do I want between the rf plate and the bottom grate?

    If the width is 45" and the depth is 28" and the height is 28", assuming my current design how tall do I want the opening of the FB to the RF chamber?

    Sorry for a lot of questions but I want toke sure this guy builds it to the right specs!
  11. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    None of them.......  the best smoker designs are on this forum.....
    weekend warrior likes this.
  12. Well its starting to take shape! Insulated Firebox was just completed and need some updated pictures of that, but for now this is where we are.

    Looks like we are going to be putting a new axle on from a seed tender and moving it back a little bit due to the weight and balance.

    I am also going to have this charcoal grill mounted on the trailer as well.

    Sorry Pics didn't work correctly before

    Last edited: May 22, 2015
  13. I have updated pics now. I didn't upload them correctly before. They should be visible in my previous post.
  14. smokejumper

    smokejumper Smoking Fanatic

    I see you went with the smokerplans hybrid.
    Maybe it is just the angle of the photo, but it sure looks like that door counterweight won't fit between the stacks. [​IMG]

    Looks like it is coming together nicely though.

    The damper between the firebox and cook chamber merely allows you to dial in increasing levels of inefficiency.

    Nothing good will come of it. I would take it out.
  15. I can confirm the counter weight has clearance. Sorry that was a bad angle.

    I plan on leaving the damper wide open To the cook chamber. The only thing I would ever do is close it completely if I wanted to cook solely in the warming cabinet.
    I am really happy how it has turned out so far. Really happy with the insulated firebox. The 1/4 inch steel cost me more but was well worth it.

    Now begins the learning curve with a stock burner.

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