Need some input and help with finishing reverse flow smoker i picked up.

Discussion in 'Reverse Flow' started by rollnthunder, Aug 11, 2014.

  1. rollnthunder

    rollnthunder Newbie

    I picked up this reverse flow project and have been checking out alot of the threads on this forum and wow there is alot of info. First a little about the pit. Its  CC measures 24"Wx60"Lx28"H the FB measures 24x24x24 and i measured the hole going from the FB to CC and its 2 3/4"x16" also measured where the RP comes to the other end of the CC and there is 4" gap. Also it has 3 - 4" intake dampers and a 3" exhaust.  Wow i think i covered most of the specs also FB is 1/4 steel and most of the cooker is 3/16 steel. Alright now on to my questions first i have been using Feldons calculator and from what i can tell the fire box is of proper size. What im not sure about is the opening in the FB going into the CC if its the right size. Im also not sure about the RP if its to far from the end or should be closer right now its 4" from the end. The next question is how high should your food grate be from the RP and should the exhaust be placed closer to the grate area or come out the top. Currently it comes out the top but i thought about making it come out right above the FB and make a 90 and go up. Any input and ideas will be awesome i got this thing for a good price and can fab anything. Thanks for all the future help and look forward to hanging out here.
  2. lendecatural

    lendecatural Smoking Fanatic

    Greetings Rollnthunder,

    Can you provide a couple more dimensions on the cook chamber? The angle the door is set at will change the volume by a good bit so if you could provide the width along the top and the height from the bottom of the cook chamber to the bottom of the door that will help in getting a good volume number so we can figure your opening requirements. Also, can you take another picture or two of the exhaust stack and how it's mounted and approximate length and diameter? Coming out the top for the exhaust isn't necessarily a bad thing but diameter and length do matter for good draw. Have you tried to cook on it yet?

  3. rollnthunder

    rollnthunder Newbie

    Thanks for the reply I have not cooked on it yet since it was bought unfinished. He has the 1/4" heat reflector plate in and he welded angle iron along the front and back wall for the supports of the grates which need to be built I figured I would just use some 1" square tube and make the frame and use expanded metal for surface. But I will take more pics tomorrow and do some more measuring for you. Thanks for any help in advance I'm amazed at all the info on this site and people helping each other out.
  4. rollnthunder

    rollnthunder Newbie

    The top of the smoker is 11.5" wide the height from the very bottom of the cook chamber under the reflector plate to the lowest part of the door is 12" the distance from the bottom to the reflector plate is 5.25". The stack is 3" diameter and is 13" tall and extends into the cook chamber about 4" Its welded in from the top but i can cut that and put bigger if it needs its. Also the opening from the firebox to the cook chamber is only 3 3/4" tall and 16" wide 


    Last edited: Aug 21, 2014
  5. lendecatural

    lendecatural Smoking Fanatic

    I plugged in your numbers and looks like you do have some work to do. Taking out the area where the door is angled, your cook chamber volume is 148 gallons. The good news is your fire box is 21% bigger than what is required, not a bad thing. The opening from the FB to CC is definitely too small, you have 60 square inches and should have 137 sq-in. That would make the opening 5 3/4" x 24, however, your RF plate is already mounted at 5 1/4. If it were me, I would leave the RF plate where it is and make the opening the full width of the CC up to the bottom of the current RF plate location. You should have 1.5 times what is recommended by Feldon's for the opening but with the lower RF plate you will end up with 1.37, it should be close enough but that is your call since it's a lot of work to raise the RF plate once its welded in place.

    Are you in a cold climate? Is the current mounting of the firebox top inline with the RF plate elevation?

    Your exhaust should be 5" in diameter and 30" high or 4" diameter and 45 1/2" and you should have about 35 sq-in of firebox intake air area. For the intakes, since your plate is low, you should have a smaller intake inline with the top of fire that will start the hot air moving towards the cook chamber.

    Good luck and keep us posted!

  6. rollnthunder

    rollnthunder Newbie

    I will take a pick of the intake system its undersized as well i think. Thanks for the all help i will check on the other things you asked for. Im also not sure how much of the reflector plate is welded in i may be able to raise it with some work. 
  7. lendecatural

    lendecatural Smoking Fanatic

    You could use 3" x 3" and have three across the bottom at fire grate level and one up in the middle of the door to help move the air. That would end up being more than needed and should flow well.
    Double check the level of the RF plate and to top of the firebox. If they are level now, you would also have to add a plate to the top of the firebox on an angle or something if you move the RF plate up. That's why I was wondering how the top of the firebox matches up. 
  8. rollnthunder

    rollnthunder Newbie

    The top of the firebox is roughly 2" above the reflector plate.Also here is a pic of what the intake setup is like also a pic of the opening in the firebox to cc

    Last edited: Aug 26, 2014
  9. lendecatural

    lendecatural Smoking Fanatic

    That's a good thing, you can cut the opening to the CC fully to the FB to maximize flow and change out those firebox intakes to get up to the 35 square inches needed. I would do 4 4" x 2" along the fire grate and another 2" x 2" in line with the opening into the cook chamber. Fire it up and give it a try, you can always move the RF plate up and make the opening even bigger without having to move the firebox since it's already mounted higher.

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