First Build Patio RF 50 gallon "Lefty" version

Discussion in 'Reverse Flow' started by radioguy, Feb 16, 2013.

  1. radioguy

    radioguy Smoking Fanatic

    Well, I've done enough reading and research, time to make some sparks!  Since this is custom why not make a left-hand version.

    Really looking forward to some smoked meats this summer!!! 

    52 gallon compressor tank dated 1927, flat rolled steel, welded rolled ends, stout and heavy.

    using Feldons BBQ calc inside dimensions:

    Tank 18" x  53" >>  13480.02 cu in    cook chamber      
    Rec fire box >>       4493.34 cu in

    Firebox size to be determined, depending on what I can procure. 

    I've got the door opening cut, hinges and flanges installed.  Thanks to SilentHunter for the hinge idea, I had some nice 3/16" stock.  I used Ribwizzard's advice on the door flanges (terrific post RW !) and they turned out great. 

    I am at a standstill until I can obtain materials for firebox.  For now I am planning on square box, 1/4" plate box.  I have an awesome cast grate from an old table saw 17" x 20", that I would like to use.

    Question 1 Firebox size, I want to make room below the grate for a slide out ash pan, do I include this additional space in FB calculation? 

    Question 2  RF plate,  I am planning on putting FB under cook chamber by about 1/3 its length.  About the RF plate, should that be welded in?  Or can I just place it on some angled brackets?  I was thinking it may be better to have it removable for cleaning.  I would take it that I want this plate to be heavy, 1/4" or thicker.  I do have some stainless stock, but it is only .120"  

    Question 3 I haven't been able to find much detail on drains, any help would be appreciated.  

    Door Cut, hinges made and welded. 

    Door flange attach.... I cut the V's a bit deeper and squared them off, using MIG here.  1/8" x 1 1/4" stock, good seal all the way around. 

    As it sits today, door and flanges complete.

    Tom -aka RadioGuy
  2. #1  Yes, I believe the firebox volume is total air volume regardless of fire placement within.

    #2  Either way would work. If it is welded in with a lip on the end opposite the firebox, it acts as a catch pan and needs a drain. If removable and not made into a pan, I would have a lip at the bottom of the firebox opening just to make sure grease does not run into the fire and cause a problem while cooking.

    #3  Not sure what you want to know about the drains. I mentioned one above for the RF plate. I have seen some with a drain in the bottom of the cook chamber too. That is up to you I guess.
  3. radioguy

    radioguy Smoking Fanatic

    Been away awhile with life in general.  But I did manage to score some 5/16" diamond plate for my firebox.  Much thanks to Dave O and RibWiz for their advice on FB and RF plate construction.  You can see that thread here>>

    I need about 17 sq. inches for my FB air intake,  I do want to place vents at and above fire grate level.  Is there any recommendation as far as what percentage to have above and below the fire??    I was thinking 2/3 at the grate level and 1/3 above it.  Any advice is appreciated. 

    Here are a few pictures of my progress. Found the tread plate to be a bit challenging since I've never worked with it before. 

    Door handle added,  not sure about counter weight and this point , it not too heavy.  I placed some stock on the door hinges as stops. 

    First corner of firebox.....done.

    Next side, trying to stay square!, next up air intake and loading door. 

  4. radioguy

    radioguy Smoking Fanatic

    I've gotten a few more things done on this build. Firebox is coming along, still have to work out door details.  My work has been a bit crazy lately and spring has arrived.  Not many pictures on this post. 

    Here are my "numbers" and RFP layout

    Please feel free to double check my layout and math, here is a link to Pit CALC,2,0,16.51,2.00&fc=7.49,10.59,44.02

    I had much trouble trying to find the center of the tank, spent much time with tape measures, strings, rigid squares on this "almost round, bulbous" object.  Then I remembered I had a simple laser level in the minutes later  we had tank center, and plumb lines for my cuts.  I was working with my college age son during this and we had some great laughs.

  5. 05sprcrw

    05sprcrw Smoking Fanatic

    Looking good and really making some head way on that cooker.
  6. raymo76

    raymo76 Smoking Fanatic

    I'm liking your build and I can't wait to see the next update
  7. radioguy

    radioguy Smoking Fanatic

    Now that I found the tank center, cuts made for firebox opening.  Used the sawz-all for these cuts.

    That being done I just had to fit it up to "see"  it for the first time. 

    Reverse plate mock-up with plywood

    I had to change the design on the air intakes.  I was going to use a rectangular slider but this firebox is a bit narrow to allow for a longer slide.

    I went with a simple threaded stopper air intake. 

    Fabricating 1/4" plate round stoppers, home made compass out of coat hanger.  This worked out a lot better than I expected. 

    Coat hanger compass

    Firebox air intake openings.  I went with the additional top air intake.  I made these all the same size about 8.5 cu inch each. 

    Still have a bit of clean up on the vents, then fabricate stopper / thread assemblies....FB door....RF least my list is getting shorter.
  8. radioguy

    radioguy Smoking Fanatic

    Time for an update on my build.  Like everyone else I've been a bit busy with summer things like gardening, paver patios and other "fun" stuff.

    I ended up re-designing the firebox door.  I was not as square as I had hoped.  I built a square frame out of 1/4" angle (3-sides).  Then placed this on / in the FB, matching the existing box.   It turned out great, good seal with 1 1/12" flat stock as the flange. 

    Hinges made from some 3/16" U stock, 3/16" flat and 1/2" bolts cut off as "pins", will use cotter pin to fasten.

    Finished the door off with cross-buck and latch mechanism.  Harbor Freight chipping hammer (got to love the price!), 3/16" stock & some 5/16" bolts as pins.  The latch engages a slot cut in the door frame.  The latch and slot are angled to tighten the door the further the handle is pushed.  

    I have the tank cut and fitted for FB opening, I won't weld together until I make some headway on cart / shelf portion.    It is getting too

    heavy and will be tough to work on without some wheels.  RF plate is rough cut and that will go in after it is wheeled and upright. 

    I only have about 1 1/2" separation between RF plate and top of FB so I am thinking about putting in another plate to deflect heat and spread out that possible hot spot.

    Thoughts / opinions are always appreciated. 

  9. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    RG, evening...   Here's a plan for the heat deflector under the RF plate and/or inside the FB.....   Dave

                 .... Click on pic to enlarge ......

  10. radio

    radio Smoking Fanatic

    Smoker is looking good!  Very close to what I would like to have if I can scrounge the materials

    Hi from another radio guy[​IMG]N6 Triple D
  11. Nice clean job!
  12. radioguy

    radioguy Smoking Fanatic

    Dave O ---Thanks for the heat deflector drawing, just a few questions. 

    What is the purpose of the spacers?  Do I really have to allow for expansion at the anchor points?  I was just planning on  installing a plate with some rod or bolt cutoffs on top

    of the FB (but in-between the RFP), and extending it a bit into the CC (3-4 inches).  My thought here is to deflect the direct upward heating of the RFP at the FB junction.  Spread it out so to say. 

    Radio  I here ya N8F double Q.  Been messing in radio ever since I got hooked @ 9 years old on CB band...before the craze. 

    Urbo   Thanks for the encouraging comment.  Just a self-taught do it your-self hack here.

  13. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Dave O  ---Thanks for the heat deflector drawing, just a few questions. 

    What is the purpose of the spacers?  Uniform air gap for insulation... The drawing doesn't show the bolts being drawn up tight so the Shield Spacers are up tight to the top of the FB or RF plate.. the spacers provide for the uniform air gap... 1/4" air gap is all you need to stop the direct heat transfer from the shield to the FB steel....

    Do I really have to allow for expansion at the anchor points? When the plate goes from 60 deg to 300-400 deg, there will be significant expansion of the plate...  Expansion gap at the bolt holes is just insurance...  maybe a 1/8" oversized hole is all you need...

    I was just planning on  installing a plate with some rod or bolt cutoffs on top

    of the FB (but in-between the RFP), and extending it a bit into the CC (3-4 inches).  My thought here is to deflect the direct upward heating of the RFP at the FB junction.  Spread it out so to say.  Extending the heat shield into the CC, if you smoker design allows is a great idea... If there is a lip between the FB and CC, install a second heat shield  under the RF plate at the entrance to the CC....  there will be significant heat on the first section of the RF plate and a heat shield is a good idea for more uniform temps across the cooking grate...

    Last edited: Aug 10, 2013
  14. radio

    radio Smoking Fanatic

    Just a noob here, but wouldn't the air intakes work better in the door where the air flow would have a straight shot over the coals and into the CC?  I know they will work in the side of the FB, but would think turbulence would cause it to be less efficient and/or have a poor draft?

    Watching this build closely for ideas or to clone[​IMG]
  15. radioguy

    radioguy Smoking Fanatic

    Dave Thanks for the clarification.....never thought about the deflector plate warping in the horizontal.  I'll post some pictures of what I decide to do.

    My thoughts here were two fold.  Vents in the door would make the door more complex, I definatly wanted a good door seal for efficiency.  Second, I did a lot of reading (search is your friend here) and there is a lot of emphasis on air friction.  Putting the air intakes on the left side of the FB allows for a straight line flow into FB and then into the CC....hope that makes sense.  Here are a couple of pix, air intakes on left side of FB.  Installed some #9 expanded on the intakes, to keep the fire in the box.  

  16. radio

    radio Smoking Fanatic

    With the new pics I see what you are doing now.  For some reason I expected the door to be in line with the FB, so knew the air friction (what I referred to as "turbulence") would have an effect on air flow.   your intake makes perfect sense now.  Never mind me, carry on[​IMG]
  17. radioguy

    radioguy Smoking Fanatic

    Time for an update on my build.  Summer got the best of me ....again.  Just not motivated to weld things during the warmer months.   I did have a fantastic garden this year.  The weather was perfect for a bumper crop of tomatoes and peppers.

    I wanted to share some the templates I devised to cut and make angles.  

    I  needed to get the final elevation of the FB and CC in order to get the stand / cart portion made. 

    I set it up, tacked the CC to the FB, set a height reference and then measured to match my height.  

    After all this is my cooker, might as be comfortable operating it.  I had to add about 10" to mocked up cooker.

    I had fabricated the axle out of some 1/4" C channel and 5/8" hardened rod.  The uprights are 3/16" U channel. 

    I made a quick cardboard template to find the angle for 1/4" angle braces.  Worked out great!

    Finished axle setup.  Rusted piece is a temporary foot until I get it all welded together.

    Cardboard template for making the cart / shelf.  I have made a number of these

    full size templates for marking the tank openings transferring angles.  I definitely 

    needed one to get these angles and fit up right. 

    Finished product.  I will use expanded steel for the shelf bottom.  The end legs will be adjustable feet with sliding square tube and 

    clevis pin for adjustment.  I wont be moving this around much.  I have plans to put a hitch on it to work with a Cat 0 mount on the 

    lawn tractor. 

    Once I get it all supported and straight I'll weld to CC to the FB,  finally coming together so to speak.

  18. radioguy

    radioguy Smoking Fanatic


    Plywood mock-up to make my smoke stack cut out. 

    Cut some OSB to the same diameter as my cook chamber.  Stapled thin cardboard to frame (great way to recycle 12 pack carton). 

    I'll cut out the cardboard, remove it from wood frame and then trace it on my tank.

     Heat deflector, used 3/8" blocks for spacers and some auto exhaust springs I had laying around.

    Threaded holes in the top of the FB.  I can remove if I don't need it or need to modify it. 

    Heat deflector mounted in FB.

    Another view inside the CC. 

    Getting closer to making one piece out of all this steel!

    Close up of adjustable legs.  Main tube is 1 1/2", foot is mounted on 1 1/4 tube. 

    Smaller tube slides inside outside tube.  I drilled incremented holes on the inside

    tube and used a safety pin from a trailer hitch for the adjustment.  I may make a trolley

    with a swiveled wheel to fit this set up.   

    Radio Gal went with me to get a drill press (Craig's list) this summer.  She has been supportive and 

    patient during this build.  Sometimes I call her the "welding widow" when i leave for long visits to the shop!.

    Any suggestions for cooking grate stops?  Keep the shelf from falling out?  Planning on using

    wide angle for my grate supports and 1" angle for the grate frames.  

  19. Nice progress.
    For the grate stops, I used a short piece of angle welded to the outside of my supports with the other leg over the top of the grate. That keeps it from tipping out. I welded a 1/4" nut in both back corners to put a bolt in so I don't pull it all the way out. Pull the bolt to get grate out for cleaning.
    You can see the small piece of angle for the top grate. The bolt hits the back if it for the stop. Just make sure it's high enough for the nut to pass under it for removing the grate if you need to.
  20. Great pic's of your build


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