Fire box size

Discussion in 'Side Fire Box' started by bethm78, Jun 23, 2011.

  1. Hello all,

    I am Beth from El Paso and I am hoping someone here can shed some light on proper firebox size.  Our back fence (brick and stucco) had a built in BBQ/fire pit that is lined with fire brick. We want to convert it into a smoker with a side firebox.  Is there a ratio or some formula to use to determine how large the size of the box and the opening into the cooking area should be?

    Any help you can provide would be very much appreciated.

  2. scarbelly

    scarbelly Smoking Guru OTBS Member

  3. Thanks. Still new to this type of thing.  I will go check in at roll call and thanks for the info.
  4. sunman76

    sunman76 Master of the Pit

    hello and welcome [​IMG]

    can you post a pic of the setup and lets see what ya got going on?
  5. Ok I will try this.  The inner dimensions are 32 W X 40 H (including arched area) X 32.5 Deep. The shelf area on the side where we were going to put the firebox is 27W X 28 D X 24H (to the flat area on the side of the pit). 

    Based on the link sent on another response if I have calculated this correctly I need a firebox 22 H X 24.5 Wide X 26 deep[​IMG]
  6. sqwib

    sqwib Smoking Guru OTBS Member

    There is a pit calculator in my signature and welcome.
  7. I found it and that and did come up with a size if I used it correctly.  I posted a pic and dimensions but when I submitted it the site said since I was new it was being held for review.  To me (untrained eye of course) it looks like my built in should make a good smoker set up.
  8. [​IMG]
  9. sorry had a duplicate
  10. scarbelly

    scarbelly Smoking Guru OTBS Member


    This is just me talking but I would turn that into a pizza and bread oven and purchase a smoker. That way you get the best of both worlds.
  11. fpnmf

    fpnmf Smoking Guru OTBS Member

    Last edited: Jun 23, 2011
  12. venture

    venture Smoking Guru OTBS Member


    However you decide to go, that is certainly an impressive structure.  Keep us posted on your plans and your progress.  I can't wait to see that baby in action!

    Good luck and good smoking.
  13. sunman76

    sunman76 Master of the Pit

    yea I was thinking something else not that awsome lookn thing.

    My first is yes a pizza oven for sure, and get you a nice smoker to go along with it[​IMG]
  14. Believe it or not I actually thought of that.  Nothing like brick oven bread but I thought I would use it more as a smoker.  We are planning to gradually turn that area into a full outdoor kitchen/ sitting area but we need to move our storage shed first. After all the reading I have done on the site I am thinking I might have to go back to the oven because based on the dimensions I think the chimney size might give me some issues.  I had given thought to the size of the firebox and intake but it never occurred to me until I used the tool that the chimney could be a prob. 

    I was worried about losing too much smoke but from what I read the chimney diameter may be too small unless I place some steel at the base of the arch on both sides to reduce the cubic inches of the cooking area.  Darn it all. But thanks for bringing that thought back up.  I just know we will not use it for a fire pit (very moderate fall and winter temps) and I have a great grill and wanted to get as much use out of it as possible and would not have to worry about rust or weather since it is so well insulated.  Decisions, decisions. 
  15. ok it is not going to work as an oven since I had the bright idea to have them stucco it when they did the fence.

    The higher temps of the oven could cause problems on the stucco overlay as it has a polymerized weatherproofing.  Should not be a problem on the sides of the oven (roughly 9 inches thick) but what would be the fire area would have to have the stucco removed from the inside and not sure if the dome is thick enough to protect the exterior from the temps.

    So will it work as a smoker do ya think?
  16. Some thoughts.

    If you use the space to the side of your oven you are going to need to limit the side of your cooking chamber anyway since the inlet for the smoke will be fairly high up the least half way up, eyeballing it. You want your smoke entering the chamber ideally below your food and circulating across/above it. If your smoke enters the chamber above the food it's going to just go straight on up and out. You could reduce the size of your cooking chamber by elevating the floor...piles of bricks with a slate on top would do it, and would be adjustable. This would in turn increase your chimney volume to cooking chamber volume ratio.

    In truth, I don't think you need to worry too much about the chimney equation. The important aspect is that it draws sufficiently but not too much, I have seen chimneys that were mathmatically "inadequate" do a perfectly fine job.
  17. sunman76

    sunman76 Master of the Pit

    Maybe you could do a center feed reverse flow of some sort that would look pretty cool.

    you would have to use the fire box dampers to control it, or I guess you could just build you in a damper

    in the top of the cook box to control for the front...duh..  thats why I dont give out much advise.

    kid creole likes this.
  18. I really like the look of that. Thanks for the pic.  That is actually the way my husband had drawn up the doors but he had the firebox on the side. He was also fabricating a damper for the top.   We really wanted to make it a built in smoker because we thought it would get more use and with as well insulated as it is on the sides and bottom temperature control would be great so long as the air flow was right.  We have been re-thinking the leaving it as a fire pit based on the advice posted here. He has also been having difficulty figuring out how he was going to be able to get the hole for the heat inlet to fit correctly.  The outer layer of the pit (sides and bottom) is 3" adobe brick (2 layers under the stucco) and then it is lined with fire brick so it is thick. which is going to make a precise cut into it difficult.  I am definately looking at some smokers to buy for the meantime because we do not want to rush whatever we do and then make the structure itself ugly and unusable. And I am ready to smoke some meat!!!!!!!!! 

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