First smoker build + a few Q's

Discussion in 'Reverse Flow' started by phaux, Jan 2, 2012.

  1. I am new to the forum and looking to build my first smoker. After reading and watching other builds I figured I would log my build as well. As this is my first build please correct me in any incorrect lingo, and also please let me know of any foreseeable problems you notice with my design.

    I have designed it in such a way that I can use the second exhaust on the left side to cook using radian heat and very little smoke when need be. The openings on the firebox and cooking tower would also allow me to use just the cooking tower and bypass the cooking chamber if I were to be cooking smaller meals. The cooking tower will also be mounted directly to the FB to conserve heat. This will all be mounted to a trailer.

    A few questions:

    1. According to the size of my cooking chamber using an online calculator, my fire box should be around 25"x25"x25". If I were to make it 24"x24"x24" what kind of impact would that have?

    2. For the FB and both ends of the cooking chamber, would there be any noticeable difference in performance/longevity between 3/16" and 1/4"

    3. According to the calculator I used, using 4" pipe it tells me I need a 55" tall exhaust chimney. That seems pretty monstrous. Am I calculating something wrong here? 

    4. What size should the pipe coming out of the top of the cooking chamber mounted to the top of the FB be?

    5. Would it be better for the smoking tower to simply cut a whole in the top and weld an exhaust, or run the pipe to almost the bottom forcing the entire chamber to fill with smoke?

    6. Will the three air inlet holes I have on the front be enough and also are they all right all on one side or should they be on different sides?

    7. How far up should the firebox be mounted on the cooking chamber?


    I've started by cutting off both ends of the propane tank I obtained from a friend. The ends of the tank will be made into decorative fire pits.

  2. fpnmf

    fpnmf Smoking Guru OTBS Member


    This site has tons of info.

    I suggest you spend some time reading all the different forums and the WIKIs.

    Ask questions and use the handy dandy search tool for specific interests!!

    Take the awesome free E-Course!!!

    Have a great day!!!

          Make bacon the easy way!!
  3. smokinal

    smokinal Smoking Guru Staff Member Moderator OTBS Member ★ Lifetime Premier ★

    Welcome to SMF! Glad to have you with us!

    Would you please update your profile info to include your location, then go on over to the roll call section & introduce yourself so we can all give you a proper SMF welcome.

    There are a lot of very talented builders on here to help you with your build. However I'm not one of them.
  4. sunman76

    sunman76 Master of the Pit

    Welcome to SmF cant wait to see you build done
  5. solaryellow

    solaryellow Limited Mod Group Lead

    Welcome phaux. To answer some of your questions, I am referencing this calculator:

    1.) According to the calculator you would be around 87% of the recommended size for the firebox. It will work although perhaps not as efficiently as a larger firebox might. I don't know that you would see a lot of difference.

    2.) If you have 3/16" already you could certainly use it. 1/4" is going to have more mass and technically last longer.

    3.) Looks right to me. You could go with 6" pipe at 25" or 35" of 5" pipe.

    4.) Size as in width or length?

    5.) Cut the hole and weld the exhaust to the top of the "tower". You won't need to run it any further down into it.

    6.) According to the calculator they are more than enough.

    7.) Just high enough to give you the right firebox opening dimensions. According to the calculator you will need 111" sq. for your opening.

    If it were me, I would also relocate the exhaust you have on the left side to the right side next to the "tower".
  6. 4. Length?

    Why would you move the exhaust on the left to the right? I have it on the left so the smoke will come out at the end of the tuning plates and go right out as to limit smoke in the cooking chamber when less smoke is wanted. The radiant heat will be used to cook the meat. Please tell me of any ideas/thoughts you have on this.
  7. solaryellow

    solaryellow Limited Mod Group Lead

    4.) Make it level with the top of the other exhaust.

    So this is more of a side firebox design with tuning plates than a reverse flow?
  8. It will be a reverse flow when the left exhaust is closed and the tower is open. When I close the tower up and open the left exhaust it will be radiant cooker. 
  9. solaryellow

    solaryellow Limited Mod Group Lead

    Interesting idea. The concern I would have is that the heat will go right out the left side exhaust and never really create enough radiant heat on the RF plate. Can't wait to see it when it is finished.
    Last edited: Jan 2, 2012
  10. fourthwind

    fourthwind Master of the Pit OTBS Member SMF Premier Member

    I agree with Solar.  I would go with 3/16 on the RF plate, and make it so that you can adjust the lower food rack so that your an inch or two from the RF plate for when your going to do your "radiant" cooking.  Then move it up to 4 to 5 inches off the plate when your using it as an RF smoker. 

    I would also plan on putting two inches of insulation between your warming box and the firebox.  Otherwise it will turn into an oven.   Fresh air vents on the back of the warming box will also help you control the temp in there.

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