My RF Vision

Discussion in 'Reverse Flow' started by smokejumper, Jun 13, 2013.

  1. smokejumper

    smokejumper Smoking Fanatic

    Started this build almost a year and a half ago.

    It is my own design that is still evolving as I think up more cool stuff to do.

    Basically a square cook chamber with some strategically placed curved surfaces to smooth airflow and reduce turbulence.

    It will be fully insulated.

    Here is how it has come together so far:

    The "Kit" consisted of 2 sheets of 1/4" cut to 20" widths, and a section of 12" dia pipe.

    First cut. Sprung 2" which is a good illustration of the stresses in a piece of pipe.

    bottom of cook chamber

    Built the tub.

    Installing the RF plate

    RF plate has a 2 degree diagonal bend that places the left rear corner 1" low for grease drain.

    Grease drain.

    Clean-out drain


    The Firebox tacked up. Got a piece of 3/8 for the floor.

    Will add a sacrificial 1/4" plate to the top.

    Strongbacks added to guard against warpage.

    Been reading about Dave's secondary high air intake, and it is a intriguing concept.

    May have to punch a couple holes in  this side.

    Fitting to the cook chamber

    Lining it up

    Tacked on.

    Face for the door seal

    Smoke stack


    where it is today

    More to come....slowly [​IMG]
  2. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    .....[​IMG]......   I'm in........   Very interesting....   Dave
  3. bruno994

    bruno994 Master of the Pit

  4. smokejumper

    smokejumper Smoking Fanatic

    A few more pics of what I got done over the last few weeks.


    Two were Tigged, the other two were stick welded.

    Hinge welding jig

    Firebox door frame.

    Putting a double-pane window in the firebox door. Tigged the small window frame.Will use combination of Mig and Stick for the rest of the assembly.
  5. dutch

    dutch Smoking Guru Staff Member Administrator Group Lead OTBS Member SMF Premier Member

    I'm in for this build. But I'm wondering if you'll have enough volume on that stack to get a good draw?
  6. smokejumper

    smokejumper Smoking Fanatic

    The volume of the stack was taken into consideration, and the volume is is per the calculator with one exception...Only the top half is fully in free air (cooler that the smoke). The bottom half is cool on one side and warm on the other. If I am not happy with the draw, the back-up plan is to add a second stack which I have made provisions for.
  7. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    SmokeJumper, evening.... One thing to remember.... In pipe, a 4" pipe has 4 times the volume per length as a 2" pipe....  2" , 4 times a 1"..... Volume is very important..... also several small diameter pipes instead of 1 large pipe is not equal.....   Friction loss from the pipe walls comes into play.... 2" = 6.28" circumference......  4" = 19.8" circumference....   4" has 3 times the surface area while it has 4 times the volume... less resistance with reduced surface area....       That's a big deal......    

  8. Hell,...I think it will work.  Might have a little "cold start" issue ( and I said might), but once temps start to get there, should be just fine.

    I think you have done a nice job there, its easy to look at the pics and see what you were thinking , and obviously you have taken the time and thought out the details. If you take the time and put the same thought and detail into the final fit and finish of this thing, you will definitely have one nice cooker when your done. 

    Only one question, do you really think that window will work good enough to be worth the effort?
  9. smokejumper

    smokejumper Smoking Fanatic

    Thanks Dave and Ribwizzard

    Yeah, I thought a lot about the chimney, and there were some trade-offs. But like I said, I can always add another. I think it will work just fine though.
    The window is purely cosmetic, so no, I am sure it will not be worth the effort.

    Thanks for looking.
    Last edited: Jun 15, 2013
  10. smokejumper

    smokejumper Smoking Fanatic

    Got a little more done this weekend.

    Cook chamber door frame

    aligned and tacked in place.

    Cook chamber top and side panels tacked in place.

    Top partially welded out.

    The 1/8" angle iron FB door frame did not work out; warped too easily.

    Gonna try a new design with a square tube frame.

    Thanks for looking.
  11. What are the trade offs for going with a square cook chamber over the typical tank style ones? Are there performance considerations? Are tanks simply more economical to find? I would imagine you could more efficiently fit cooking racks into a square cook chamber like this one. 
  12. smokejumper

    smokejumper Smoking Fanatic

    Hey Munxcub,

    Most people start with a tank cuz it saves work building up a cook chamber, and it is a proven design.[​IMG] And they look good.[​IMG] And they are generally more economical to find.[​IMG]

    I believe that performance-wise there is nothing wrong with tanks, and I would not hesitate to use one.

    On this buiId I went square cuz I wanted maximum rack space in a patio-size offset cooker, I did not already have a tank, and there are some design elements I am using that are better suited to a square CC.

    Once I settled on a square CC, I added curves and bends in some places to smooth the airflow, reduce turbulence and improve efficiency.
  13. I can see that.............your .doing a real nice job at that
  14. Nice job with good ideas SmokeJumper.

    I have to add that a long time ago I thought about having a window into the cook chamber. You would need a square smoker like yours and mine turned out to be round.

    Still I think it would be worth the effort to put your double pane windows for looking at the meat while smoking. Then while you were looking you would still be cooking. Of course the design I had in mind would require 2 windows. One on the door and one other window to let some light in to be able to see the meat. It never went past the planning stages so I don't know how much could be seen while smoking your vittles. As for glass I was looking to rob double pane oven doors as they were already pyrex to withstand the heat.

    Lots of luck 
  15. Thats what I was thinking, use an oven door instead of trying to make one. Once its painted black it should look alright. Especially one off a newer stainless model.
  16. smokejumper

    smokejumper Smoking Fanatic

    What I went with was replacement glass for wood stoves. It is actually a clear ceramic that can take temps up to 1250 degrees. Not too expensive. Heck, the shipping was nearly as much as the windows.
  17. smokejumper

    smokejumper Smoking Fanatic

    Here is what I got done the last two weekends:

    Finished welding out the cook chamber and got the cooking grate rails installed.

    Made grate frames and finished two grates but ran out of expanded metal for the third,

    Next up is to work on the doors,

    As always, I welcome your feedback and suggestions, and thanks for looking.
  18. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    SJ, evening...... Well..... How's it coming..... Dave
  19. smokejumper

    smokejumper Smoking Fanatic

    Hey Dave -

    Well, I did finish the third cooking grate, and got the firebox door started.

    Kinda stalled at that point.....
    The company I work for moved our production line to Texas, so I have been traveling to TX every other week for the last three months, leaving no time to work on it.

    Now that I am back home for the foreseeable future, I should be able to get back on it. I will have a week off for Christmas, so we should see some progress then.

    I'll keep y'all posted.
  20. smokejumper

    smokejumper Smoking Fanatic

    Well, I finally put in some more time on the smoker.
    Here is what I got done today....

    Installed handles to the racks.

    The racks have 5/8" square tube frames that did not seem stiff enough across the length of the grates.
    I decided to make the handles into a truss to stiffen it up. Worked great. No worries about loading these up.
    One rack has a handle facing down so that I can have easier access to small or flat items without pulling the grate out.

    To keep it out of the way of taller items on the lower rack, it can be installed on the bottom rear out of the way.

    Got started on the Firebox door frame. Using square tube this time.

    The rods are the hinge pins for the swing arm style hinges.

    Used levels and rulers to make sure the rods are parallel to each other and to the door frame.

    That is all for now.

    As always, comments are welcome, and thanks for looking.

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