Draft Problem

Discussion in 'Smoker Builds' started by tabasco, Jan 21, 2016.

  1. Okay, first time posting and looking for some help  I am trying to get a friends vertical offset to maintain a good cooking temp but i cannot. It just does not seem to draw well enough. I cannot get it to hold much above 200 with charcoal only. The tank is 64 in tall with a 24 in diameter. The opening between the firebox and the tank is a 6 in circle. The firebox has expanded metal with 3 in of clearance off the bottom for air.  The vent is a wheel type with two triangular slits that are 3 in at the widest point. I thought the 4 in hole in the bottom for the supplemental gas burner was letting in cold air so i added the pictured pipe on the bottom. I cut off the hole completely and that was not the problem. My hunch now is the stack may be too small. It is a 3 in pipe having a 2.5 in ID. Does anyone have a formula used to figure stack size? My simple way of thinking tells me the vertical configuration is ideal for drafting, much like a chimney in your house. I would appreciate any and all help on this. It is a very versatile unit and i would love to get it working at its maximum efficiency. Thanks


  2. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    How big is the opening between the FB and the CC ??    

    The door appears to need seals to stop the air leaks..

    The exhaust is WAY too small..  I would put exhaust holes around the top of the straight section of the walls.... Probably start with 4 each 2.5" pipe welded in place... threaded so caps could be installed... Those 4 nipples would be equivalent to one 5" hole...  that prevents condensate from dripping on the food....


    Last edited: Jan 22, 2016
  3. So is the spacing all around the unit what prevents condensation? Would two 4in stacks on the off side from the FB do the same thing? Also, what about the length of the stacks?
  4. The hole between your cooking chamber and fire box sounds small
  5. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member


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