Will this work? Has anyone tried an undersized fire box.?

Discussion in 'Smoker Builds' started by bjons, Jul 12, 2011.

  1. bjons

    bjons Newbie

    My only fire box I've been able to get my hands on is 5000 less cubic inches than the calculator says it should be. My cooking are is round with a dia. of 29inx82in. the fire box i want to use is dia of 19inx47in. Can this work? any help would be welcome as im getting pinched for time.
  2. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Bjons, evening.

    Someone spent quite a bit of time figuring out the calculations for making a great smoker.

    That being said......I would not change the ratios of fire box to cooking unit. I'm not that smart.....but you already knew that.....Dave

    PS Welcome to your new home.
  3. got14u

    got14u Master of the Pit OTBS Member SMF Premier Member

    Don't go below 1/3 of your cooking or smoke chamber....and that sure seems like a LONG fire box to me any ways, almost 4' if I am reading it right
  4. solaryellow

    solaryellow Limited Mod Group Lead

    There are plenty of undersized fireboxes in some of the builds here. It will work but will consume more fuel.
  5. got14u

    got14u Master of the Pit OTBS Member SMF Premier Member

    How does it consume more fuel?
  6. solaryellow

    solaryellow Limited Mod Group Lead

    Think of it as a tank full of hot air. The smaller your tank of hot air is, the easier it is to cool that tank of air with the introduction of cooler fresh air thus needing a hotter fire to keep the hot air flowing. Put an ice cube in a small glass of warm water and then put an ice cube into a large glass of warm water and see which one gets colder. Does that make sense?
  7. talan64

    talan64 Meat Mopper

    Are you completely stuck on using a round firebox?  If you were to go with a square fire box, you should be able to get away with (roughly) 29x25x25 (correct my math if wrong). 

    Of course the experts here on the site can tell you better, but I do agree that with the canister style firebox you are suggesting it seems rather long.
  8. What configuration are you contemplating? SFB? If so, the smaller diameter of the firebox and the long shape of it present problems as far as the draw is concerned you may get a bit of a "venturi" effect and burn even more fuel than you need. If I were you I would consider building a square firebox to suit and ditching the pipe.
  9. meateater

    meateater Smoking Guru SMF Premier Member

    Last edited: Jul 12, 2011
  10. bjons

    bjons Newbie

    Ok, we did our first test burn to check draft. worked great with the exception that i was unable to throttle the temp down enough. I used a bad of kingsford for this test burn. Will using wood allow better control of the temp?[​IMG][​IMG][​IMG][​IMG][​IMG][​IMG][​IMG]

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