1st build, few questions

Discussion in 'Reverse Flow' started by thedickens, Nov 2, 2014.

  1. thedickens

    thedickens Newbie

    Good afternoon,
    Been lerking for a while but finally decided to join and ask a few questions. This will be our first smoker. Husband family had always used a side firebox, but it seemed to use a lot of wood, and we had to move meat around otherwise it would crispy by the fire box. Result they often wrap the meat in foil which seems to defeat the purpose of smoking :) After doing research on here we've decide to give RF a try. He found a 250 gal propane tank, we've cut the rounded ends off (plan to make fire pits and sell them).
    CC is 30x70 = 49500 cu in
    FB is 29x24x24 = 16700 cu in
    Plan to put the RF plate 10" from the bottom
    Using the half moon the FB to CC would be 205 sq in
    These seem to all be in line with the numbers I've found on the forum. here are the questions I have so far.
    Chimney - does it need to be round or can it be square. Math wise a square would allow the chimney to be shorter since a 3 in sq has more area then a 3 in circle.
    Doors - do the doors have to open at the top, I've always had an issue with not being quite tall enough to get the door to flip over, or to be able to reach the handle to shut the door. Opening from side would make it easier, but it's a 28ish door.
    Hinges - is there any advantages to a three piece hinge where one is on the door fits between two on smoker with a pin through it, verse an l shape. I'm sure I'll have more questions but that's all I can think of at the moment.
    Last edited: Nov 2, 2014
  2. wolfman1955

    wolfman1955 Master of the Pit

    IMHO You may want to save one of those ends and weld it back on! The rounded end helps with the smooth transition for heat and smoke at the end oposite the fire box. Some one with alot more knowledge than I will help you out.
  3. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Square exhaust stack has more surface area per cubic inch of volume.... That equals more friction and loss of flow....
  4. A question I have regarding the build and the exhaust.
    Is it better to have the exhaust at the top of the cook chamber or lower down the side say just above the fire box?
    My thoughts are lower on the side so you don't get a dead spot above the fb opening.

    Any thoughts on that one
  5. wolfman1955

    wolfman1955 Master of the Pit

    I am sure Dave Omak will be back to answer your questions. He is a build and design wizzard. He will not stear you wrong!!
  6. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    There are folks that have found different outcomes from stack placement... The main thought, that I have determined, is stale smoke flavors... that comes from "dead air" in a smoker regardless of design... When smoking meats, air flow seems to be a critical element to get good flavor....

    Below is a smoker by ultralow787..... The plenum, on the exhaust, allows for smoke/air to be drawn from a wide area in the CC.... The lower air inlets in the FB allow for temps adjustment to the fire, and more importantly, increased air flow, using the upper inlets, without adding heat by fanning the fire....

    This smoker, appears to have an oversized FB which makes for easier temp control...... (If the smoker is air tight) A very well sealed smoker, is critical to overall control...

  7. thanks dave. yea i plan on having an upper and lower vent but also a flue baffel. i might have an idea which will allow draw over the complete height of the smoker.. ill keep you posted on my build
  8. thedickens

    thedickens Newbie

    Well, we finished the smoker, with the gauges centered in the doors (which happens to be nearly the height of our second rack) we are seeing maybe a 10 degree difference between the sides, with the turn around being hotter then the fire box side.  First attempt at cooking, has me confused.  Doing a brisket, it ended up being 9 pounds once trimmed.  Figured on a 9-12 hour cook/rest time so put it on the smoker around midnight with gauges showing 220-230. 4.5 hours later it has an internal temp of 190 and the desired tenderness.  How can it be done in half the anticipated time?  We cooked it on the lower grate (about 5 inches above the RF plate) on the firebox side.  I'm assuming my lower grates are hotter then the gauges are showing.  Did we do something wrong on the build or is this normal?  Should we put another set of gauges at this rack level?
  9. Need to see some pictures of your smoker

  10. I found that I never use the stack damper to control heat. I leave it open 100% during the cook and control temperature with the dampers on the FB. I do have the lid on the CC sealed with a gasket. I did have to increase the size of my FB coal basket and I'm happy with the operation and performance.

    I close off the top stack damper to extinguish the fire when done cooking.

    This site was such a huge assist to me with this first build!

    I received a 18.5" WSM as well for Christmas to add to my arsenal. This winter can't end soon enough so that I can get back at it. I have a 12 pound packer brisket in the freezer just waiting for warmer outdoor temps.

    Happy New year all!
  11. thedickens

    thedickens Newbie

    Pictures of Smoker as requested.  Husband liked the look of flat ends, so even though it was suggest,he decide not to weld the cap back on.

    the CC ended up being approx. 70 long by 30 dia, the fire box is 24X24X29 and currently is just 3/16 steel, we had planed to line the bottom with fire bricks.  We have two cast iron flat fireplace grates (11x17 I think) without the bricks the top of the grates sit in the middle of bottom sliding adding the brick would put the airflow above the brick and below the grates.  The end cap on FB side is about 18 inches tall, FB mounts directly to this resulting in a 10 in tall half moon FB to CC opening. Rewelded the half moon cutout at an angle as if it was just pushed into the CC.  Stacks are 3.75" and about 4 feet tall


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