Smoker Help - more air?

Snowsmoke · Posted: Apr 28 2016 Post subject: Smoker Help - more air?

I got myself a stick burner that I can't seem to dial in and I am starting to think it isn't drawering enough air. The Q is often over smoked no matter what the wood choice is b/c maybe the fire is smoldering verse burning correctly? Aaron Franklin has a big old section in his book about this and offers long smoke stacks a part of his secret plans.

I commonly see smoke coming out of the fire box the wrong way even while the smoker is coming out the stack nicely. Any help from the experts here would be a huge win for me.

The smoke stack is 4" x 3" metal stock. the fire air intake is 6" x 6" and the hole from fire chamber to cook chamber is 10". the cook chamber is a 200 gallon water tank.

Smoker (sorry for the links)
https://www.dropbox.com/s/qkyb52d5x611rpp/IMG_1988.JPG?dl=0

https://www.dropbox.com/s/d18unv41ntzlbz8/IMG_1987.JPG?dl=0

https://www.dropbox.com/s/ehhvh0j406dbeg5/IMG_1989.JPG?dl=0

https://www.dropbox.com/s/9z5dlqcu192zcfz/IMG_1990.JPG?dl=0
_________________
"The Moon ain't romantic. It's intimaditing as Hell" - Tom Waits (maybe he was up at 3am to BBQ too!)

Smokin Mike · Posted: Apr 28 2016 Post subject:

You didn't mention the size of your firebox.

Using Feldon's pit calculator for a 200 gallon tank;

Recommended firebox size = 15,400 cu in which would be a cube 24.879 inches.

For arguments sake I'm plugging in 25" cubed as the firebox size.

You should have a chimney volume of 781.25 cu in. The 4 x 5 chimney should be 39" long (39 x 4 x 5 = 780).

Recommended firebox air intake is 46.88 sq inches whereas yours is currently 36 sq in.

The firebox to cooker cutout should be 125 sq in and yours is 78.5 sq inches, so that looks to be the biggest culpret right there.

Here's a link to the calculator with your settings in there. You can play around with it to fine tune for your setup;

Link to BBQ Pit Calculator

I hope this helps
_________________
My current cookers: 80 gallon vertical tank
The Ultimate New Braunfels Makeover

Maniac · BBQ Super Pro Joined: 02 Oct 2010 Posts: 2433 Location: Pa

The other thing that may be causing a stall is your stack is lower than your firebox...looks like you may need a few different modifications to fix her right.
_________________
RF Smoker
20" disc
uds

k.a.m. · Posted: Apr 28 2016 Post subject:

Your biggest set back is your exhaust. You need to increase it to at least a 5" diameter I would probably go 6" and make it 36" tall. The current 3" x 4" is not creating enough draft and while you are seeing smoke exit the exhaust you are not creating a draft and your smoke is stalling. Once this is done I would probably work on the firebox to cooking chamber opening. What are the dimensions of your firebox?
_________________
Always remember slow and steady wins the race.

Hybrid Cooker

Snowsmoke · Posted: Apr 29 2016 Post subject:

Very helpful all!

the FB is half a 125 gallon compressor tank but I would have to actually measure it to get the exacts.

Thanks Smokin Mike and K.A.M, for all the suggestions. Bummer it might not work just to extend the stack though it seems like no harm in trying with some stock and heat tape though I dbout the results would change. Looks like I should take the welding class after all and keep working on this little lady!

I will fine tune all your thoughts with the calculator too.
many thanks.
_________________
"The Moon ain't romantic. It's intimaditing as Hell" - Tom Waits (maybe he was up at 3am to BBQ too!)

k.a.m. · Posted: Apr 29 2016 Post subject:

Madmike · Posted: Apr 29 2016 Post subject: Modify Smoker

Snowsmoke, the small firebox to cook chamber opening, combined with the small stack mounted so low is definatly a lot of the problem, that stack needs the diameter increased as well as moved up. How are you equipped for tools etc, my garage I rent to build my smokers isn.t that far away if you wanted to take a ride down with it,i could open up the fb to cc opening in a few minutes with my plasma cutter as well as cut a new opening for a larger stack if you don't have torches etc. Just bring the beer, we're over the garage every sat and sunday,and I'm there a few hours a day weeldays while my leg is still broken, I can't do the day job,
might only take a few hours to straighten her out Idea

Mike
My garage is in Whitman Mass
_________________
Never met a Pig I didn't like !!

k.a.m. · Posted: Apr 29 2016 Post subject: Re: Modify Smoker

Snowsmoke · Posted: Apr 29 2016 Post subject:

Wow that is super nice of you, and I will shoot you a note!

Since you guys are so helpful my FB is 19.5" in diameter X 28" in length

the CC is 29.5" in diameter and 63" in length.
_________________
"The Moon ain't romantic. It's intimaditing as Hell" - Tom Waits (maybe he was up at 3am to BBQ too!)

Maniac · BBQ Super Pro Joined: 02 Oct 2010 Posts: 2433 Location: Pa

Madmike Great offer. that is what makes the ring a nice place to hang out Cool

_________________
RF Smoker
20" disc
uds

Smokin Mike · Posted: Apr 29 2016 Post subject:

Madmike · Posted: Apr 30 2016 Post subject: FIREBOX

Yeah, I ran the calcs also Might be able to just add a plate fbox the right place where his original opening was,and block off any xtra opening with plate. I get plate for 40cents
a pound,so I keep lots on hand. Iget sheet length cutoffs in all different widths,so I can usually fab a fbox without a lot of cutting !! Wouldn't be worth messing with the small fbox, just fix it right and be done!!
Mike
_________________
Never met a Pig I didn't like !!

Madmike · Posted: May 01 2016 Post subject: Rebuild !!

Snowsmoke sent me pics and measurements, so I ran the specs,and can fab up a new fbox before he comes to the shop to fix it, lets me put the leg up and sit in a barstool at the welding table with a cold one while I do it !!
Mike
_________________
Never met a Pig I didn't like !!

Snowsmoke · Posted: May 03 2016 Post subject:

literally the most help smokeringer I have ever met!

thanks to all the chimed in, will send an update once the corrections are made to fill everyone in.
_________________
"The Moon ain't romantic. It's intimaditing as Hell" - Tom Waits (maybe he was up at 3am to BBQ too!)

k.a.m. · Posted: May 03 2016 Post subject:

Looking forward to seeing the results. Very Happy

_________________
Always remember slow and steady wins the race.

Hybrid Cooker

Madmike · Posted: May 03 2016 Post subject: Rebuild

Found some plate today that was already 24 inches wide behind a wider sheet,so i'll cut the firebox pieces tomorrow,while I'm cutting some other plate for a smaller smoker,and a couple doors. That thing was built for mike at a shop on the same road as mine 4 miles from me !!
Mike Rolling Eyes

_________________
Never met a Pig I didn't like !!

Madmike · Posted: May 04 2016 Post subject: Cut Mikes new Firebox Plate

Cut the new plate for Mikes Firebox today, I'll tack it together tomorrow after I cut the Firebox Vent openings. I'd post pics, but I totally give up on that!! too hard for an old non computer guy!! Confused

I emailed them to Mike, so at least he can see his mods. I have a pattern for the 29-31 inch diameter propane tanks,so I'm just working off that to prebuild his new firebox.
Mike

Kinda weird the guy near me who built Mikes smoker is named Mike, and I'm Fixing it, and my names Mike !!
_________________
Never met a Pig I didn't like !!

Snowsmoke · Posted: May 05 2016 Post subject:

Progress from the Madmike camp on the FB

BRING ME ALL THE METAL!
_________________
"The Moon ain't romantic. It's intimaditing as Hell" - Tom Waits (maybe he was up at 3am to BBQ too!)

Smokin Mike · Posted: May 05 2016 Post subject: Re: Cut Mikes new Firebox Plate

Wreckless · Posted: May 05 2016 Post subject: Re: Cut Mikes new Firebox Plate