Custom build, air flow question

Discussion in 'Smoker Builds' started by dowquest, Oct 31, 2010.

  1. dowquest

    dowquest Fire Starter


    I am finishing up my custom build smoker, and am pondering the air flow in the smoker. I see two options, dispersing the heat/ smoke through multiple holes in the bottom heat plate above my ports coming from my firebox, or a crossflow . I am concerned with a hotspot around the x in the picture though. Any thoughts Ideas? Sketch isn't 100 to scale, just for demonstration, the chimney, comes down inside to the grate height.  Any thoughts appreciated.

  2. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    Not sure exactly what setup you are planning but here is what I may try with the fire box ports right in the center.


    Not sure if this is what you are asking for but I hope it helps. And this is just what I would do if it was me. There are several ways to do it.

    Good Luck and pls post up some pics of the progress.
  3. dowquest

    dowquest Fire Starter


    Thanks for the reply, it does answer/ confirm my questions/ thoughts.  I built it this way to minimize the footprint, I'll give what you described a shot and see what happens. I can always add holes in the middle and right side to balance out the heat as you suggest.. When I have a chance, I'll add some pictures.

  4. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    Good Deal and good luck.

    With holes like that, with patience you should be able to get the temps dead nuts on target across the grate.
  5. dowquest

    dowquest Fire Starter

    Alright, I managed to get the heat/ flow plate installed, and Plasma cut 6 holes in the middle and right side of the chamber. I still have the plugs, so if it gets too hot in any area, I can weld them back in. Next week, I'll make the rack, and install the lid, then, it's getting close...

  6. dowquest

    dowquest Fire Starter

    Getting closer. Installed the flow plate tonight. Started off with 6 holes 1 1/2" roughly in diameter in the middle and right sides of the plate. Maybe 3 or 4 more nights, and it'll be test time...

  7. dowquest

    dowquest Fire Starter

    As a follow up, What should I do for a drip pan? I currently use a Brinkman H2o smoker, that I have modified so it would actually work,  but with this, I was thinking of an elevated pan between the grate and heat plate. Thoughts?
  8. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    Maybe you can use a bakers rack sitting on the plate and then have something like a cookie sheet on that. I have never tried anything like this but I would almost think it may affect the temps across the grate. Then again maybe it will help.

    BTW....Thats a pretty slick looking rig you ended up with.

    Nice work.
  9. dowquest

    dowquest Fire Starter

    Thank you.

    I'm not sure how much it would affect the temps. I would think it should be pretty even throughout the cooking chamber. I'll be giving it a  test run here in a couple weeks, we'll see.
  10. dowquest

    dowquest Fire Starter

    Getting even closer.... wood for the handles, and some expanded steel for the firebox, and installing the smoker door gasket and seasoning...

    Last edited: Nov 11, 2010
  11. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    That looks awesome. You have a very nice size cooker that only takes up a small footprint of real-estate. Hey, watch out loading hot dogs and brats on the grate, LOL you may loose one.

    I really like the vent on the firebox.

    In case you decide you want, you can link the video in your post. Just click the filmstrip next to the img button, paste your tube link and hit submit.

    Nice Work.
  12. dowquest

    dowquest Fire Starter

    Test cook last night, 2 cans of coals brought it to 250*, 3 to 300*, let it cook the gasket on the lid for 45 min, then choked it down to 250* and let it go for the night. Found out when I dropped my thermometer in the hardware store, it must have messed it up, it was around 50* low. Confirmed this by my remote meat thermometer stuck through a potato sitting on the grate. Luckily ( I guess) I have already ordered a replacement since I cracked the glass trying to get rid of the dent the floor made when I dropped it. Any way, Doin' a turkey and some corn on the cob Monday. Will post a pic or two of the final project.
  13. dowquest

    dowquest Fire Starter

    OK, 12# Turkey was smoked to absolute perfection last night... I used a roasting pan, for 2 reasons, 1 to keep the drippings off the diverter plates, and 2 to keep for gravy, (Which was absolutely incredible) It ran for ~7 hrs at 250* and was finished at 170*. Totally happy with the design of this smoker, and it's operation. It holds the temp really well, and is easy to adjust if needed. I never did install a diverter into the firebox pipes like I had thought I would need, but I really don't see a benefit to using them as long as you keep your fire in control.

  14. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    Great looking bird.

    Glad to hear the design worked out for ya.

    You have a very nice looking rig there.
  15. dowquest

    dowquest Fire Starter

    Thanks Tom,

    Finishing up some hardwood handles for it, should have finished pics in a few days. couldn't have produced such a nice smoker without the help here in the forums. Thanks to all for answering my newbie questions.

  16. dowquest

    dowquest Fire Starter

    Finally finished. Just in time to head for the beach camping over Thanksgiving.[​IMG]

  17. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member


    Those wheels are probably not going to do very well in the sand!!!!!

  18. dowquest

    dowquest Fire Starter

    Thanksgiving cook report......

    not so good.

    I had 2 - 12 1/2# turks on the grill, and it was keeping a consistent 250*, Around noon, my buddy asked if he could throw in his ham to warm it up( 40* out of the refridg.) I said sure... (This decision may have been hampered by the 2 hrs of drinking, as it was already noon..)

    That was the turning point, I tried to bring the temp up, but could not, as I would light of cans of charcoal and throw them in the firebox, the temp would not increase, even with the air vent wide open, actually, this seemed to suffocate the existing coals. I began stirring the coals, as the back side was black, and the front was red hot. All this seemed to do, was stir up the ash, and deposit it on the turkeys.

    Long story short, 2 hrs after they were supposed to be done, I pulled the now ash covered birds from the smoker and finished them off in the oven, the ham came out good.

    Lesson learned, In the design of the smoker, I assumed the coals would draw fresh air from the vent under the coals, to the back of the box, utilizing the whole firebox, this was not the case, as it was designed, it only is using 1/2 the firebox at the most.  Secondly, don't stir the coals.

    Mods made the next day.

    A ~2" hole was drilled in the lower end of the firebox opposite the air vent ( installing another 4" vent will be done Saturday) 2 days after Thanksgiving ( Saturday) I cooked Ribs with the mentioned mods. The firebox ran hot front to back, and for a 6 hr cook, I used only a fraction of the coals I had previously. For my next cook, I will try loading up the firebox with coals, and do a temp control with the vents only. Saturday's run was coal based, and I had to add coals every 45 min or so.

    Thoughts, comments welcome.
  19. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    Gol-lee not even one comment about rolling it in the sand. [​IMG]

    Sorry I couldn't help myself.

    Also sorry to hear about the misfortune with the ash covered birds. With every rig and every fire box, things are going to be a little bit different on how well they run. This is why the big names have the big price on there rigs. They already did the do-overs and worked it out.

    Sounds like you had the adapt and overcome theory and it worked. At least the day of ash wasn't a total loss and the ham turned out.
  20. dowquest

    dowquest Fire Starter

    HaHa, yeah I thought about it, but couldn't come up with anything good. We actually had the turkey's the next day, and they were good, but not as moist as they could have been, which only I knew, but everyone else was happy.

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