Newbie 200 gallon RF build

Discussion in 'Reverse Flow' started by timbercop, Apr 1, 2013.

  1. Hey folks. 

    Getting ready to cut steel on a 200 gallon air compressor tank (built in 1963) to build a RF smoker and have a few questions.  The calculator has been a big help in a potential design.  It is 7ft long, 30 inches diameter, 3/16 in thick.  I've looked through plenty of the threads, but maybe I've missed these.  If they are repeats, I apologize.  

    I decided I don't need 7ft so I am going to cut 2ft off and use it for the firebox.  I don't have access to a torch, so what would be the best method for cutting a straight line?  I've got an angle grinder with cut off discs and they done well on cutting some of the welds off.  Would this be enough?  Maybe a circular saw with a cutoff disc?  Suggestions?

    Will the section I cut off be enough for the firebox?  Any reinforcement needed? According to the calculator, a 2 ft firebox on a 5 ft food chamber is 101% of what's needed.  I am planning on getting two pieces of 30 in round steel, at least the thickness of the tank to fill in where it is cut and for the door of the firebox.  

    On the RF plate, how thick does it need to be?  Also how big does the opening need to be from the RF plate to the food chamber.  The calculator didn't mention it.  

    Any suggestions will be greatly appreciated.  

    Thanks folks.  
  2. Cut off wheels will work fine for cutting the tank. A lot of folks use that method. The torch is just quicker and easier if you have one, but not necessary.

    I did the same thing with my tank to make the firebox. My tank is 30" diameter. THe firebox is 25" and the cook chamber is 65". That is measured out to hte end of the rounded ends. Some don't like the round firebox, but why not use what you have. It was pretty easy to work with that way. When you get the two pieces joined together I would get some cardboard and make templates to cut out the end caps. That worked out great for me.

    I would not go thinner than 1/4" for the RF plate on this size tank. From what I have found it is normally recommended to have 1.5 times the size of the FB to CC opening under the RF plate and for the opening to the CC.

    If you want to see how mine was put together it is here

    I am heading home from work in a few hours and plan on working on it some the next couple days.
  3. I used a wraparound to make the straight line for cutting the tank apart. I had one when I was fitting pipe, a welding supply place should have them. It worked great. I'm not sure of any other way to make sure you get a straight line.
  4. Your design looks great. On the firebox, I was planning to have the flat side on the outside for the door, I guess I'll have to look at it when I get it apart.  Also like the food chamber door hinges you have.  I was still debating those.  I'll put up a sketch of mine tonight.  I'll look into getting a wrap around for the straight line.  Thanks for the info. 

    I'm sure I'll need some help on getting it set and balanced on the trailer once that stage comes along.  
  5. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Copied from the calculator....  I recommend 1.5 times the FB-CC opening to reduce friction loss when the air/smoke/heat takes a 180 deg turn....     Dave

      • If this will be a Reverse Flow smoker, then the opening at the opposite end of the cook chamber from the fire box should be at least as large as the firebox-to-cook chamber opening.
  6. Thank you.  I missed it.  
  7. Still working on this build and ran into a couple of questions.  

    1. How far down into the tank should the chimney be?  Near level with the food tray, or near the top of the tank?  

    2. The firebox to food chamber hole is not at the highest point on the firebox.  Should I be worried about heat gathering in the top of the firebox and not flowing well into the food chamber? 

    I'll have some photos in a few days.  The only thing I have left on this is getting the reverse flow plate, grates for the food trays and some welding.  
  8. A couple of angles.  It's the only recent pics I have at the moment. 

    Thanks for any input. 

    Last edited: Aug 29, 2013
  9. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    These designs work........    Dave

  10. Thanks Dave.  I'm certain I'll be back on in a few days with a question or two.  I'll get some other pics as well.  

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