Reverse Flow Smoker

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BarnMB
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Reverse Flow Smoker

Post by BarnMB » February 24th, 2018, 2:25 pm

Hi I’m not sure if this is the right place to post but I’ll give it a go. In the past year I started to build a reverse flow smoker. Not everything is complete as I wasn’t sure I wouldn’t want to modify it. It seems to use a lot more charcoal then I would have thought it should. Any help would be appreciated. The firebox is an old wood stove and measures 18”x32”x an average of 20” high. The cook chamber measures 16” diameter and 60” long. The stack is 4 3/4” id and 32” tall. Is the firebox the problem?


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Re: Reverse Flow Smoker

Post by Rodcrafter » February 24th, 2018, 4:02 pm

My experience with offset smokers is they work better burning wood. Now I can’t run the numbers through the pit calc right now, but the picture shows the top of the FB is open like for a grill. Does it close and seal up when smoking? What is the smoker doing besides using too much fuel?


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Re: Reverse Flow Smoker

Post by BarnMB » February 24th, 2018, 4:29 pm

No it is completely closed off there. It’s a separate grill for doing meat on skewers sort of churrascaria style.


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Re: Reverse Flow Smoker

Post by Big T » February 24th, 2018, 4:37 pm

Welcome aboard!! :yth: The FB is about 260% of the recommended size so that doesn't help with efficiency. What size is the throat and BP gap ?


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Re: Reverse Flow Smoker

Post by BarnMB » February 24th, 2018, 7:08 pm

So it would help the efficiency a lot to make it smaller? I just happened to have the old stove lying around and figured why not use it. Ok Between the firebox and the area below the baffle plate the opening is 12” wide and 3.5” tall semicircular on the bottom and flat on top. At the end of the baffle plate where it goes around the corner to get into the cook chamber it is 4.5” across in the middle and semicircular sort of as well. See attached pic? Is that what you meant? Sorry I’m such a newbie!
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Re: Reverse Flow Smoker

Post by BarnMB » February 24th, 2018, 7:24 pm

To bad I never found this site before I built my smoker. I see one smoker plans.net they have plans for 16” air and propane tanks like mine is however the lengths are different then mine. If I bought one of these sets would any of the dimensions change other then the length of the tank? If not I could buy a set and modify mine to fit that plan.


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Re: Reverse Flow Smoker

Post by Dirtytires » February 24th, 2018, 8:32 pm

Did you use the pit calculator to find all your dimensions and then compare them to yours? The calculator is located on the navigation bar at the top of the page.

The throat is the cubic inch opening between the firebox and cook chamber and the baffle plate gap is the opening at the end of the baffle plate within the cook chamber. It also gives you the volume of the chiminey and a bunch of other valuable info.

Take a minute t run your numbers and let us know actual from recommended and we can help you fix them.



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Re: Reverse Flow Smoker

Post by BarnMB » February 24th, 2018, 9:08 pm

Dirtytires wrote:Did you use the pit calculator to find all your dimensions and then compare them to yours? The calculator is located on the navigation bar at the top of the page.

The throat is the cubic inch opening between the firebox and cook chamber and the baffle plate gap is the opening at the end of the baffle plate within the cook chamber. It also gives you the volume of the chiminey and a bunch of other valuable info.

Take a minute t run your numbers and let us know actual from recommended and we can help you fix them.
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Re: Reverse Flow Smoker

Post by BarnMB » February 24th, 2018, 9:28 pm

So that’s what I have and this is what I should have I guess. Looks good once the firebox is knocked down in size? I guess it’s time to start modifying. Should the stack be smaller diameter now so it can be taller? Many thanks for all the help so far! I had never seen one of these in person before I started building it. Image


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Re: Reverse Flow Smoker

Post by BarnMB » February 24th, 2018, 9:34 pm

Currently very close on this if I make the firebox as small as the last calculation I sent.

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Re: Reverse Flow Smoker

Post by Dirtytires » February 24th, 2018, 10:24 pm

Chiminey legnth is 28.75 from the calculator...you marked 10inch in your spreadsheet. Legnth or diameter really isn’t the concern, it’s the volume you want. Most people try to get the exhaust high enough to keep the smoke out of your face yet short enough to fit in the garage. I’ve seen from 2inch to 6 inch with most common around 3-4 but yours is fine. Just trim it to proper legnth.

Everything else looks pretty close. I would start by decreasing firebox size as mentioned. Again, it’s the total volume that matters, not a perfect shape. Looks like you could pretty easily cut some legnth off yours.

It looks like your intake needs a bit bigger also. It looks like you only have 0.8 of the required 2 intakes. Again, need total sq inches....qty doesn’t matter.



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Re: Reverse Flow Smoker

Post by Big T » February 24th, 2018, 10:45 pm

It looks like you're on the right track now with some help from the guys. Once you get the dimensions corrected you should be able to get a bed of coals and only have to add a small spit or 2 of wood every 45-60 minutes.
Last edited by Big T on February 24th, 2018, 11:06 pm, edited 1 time in total.


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Re: Reverse Flow Smoker

Post by BarnMB » February 24th, 2018, 10:53 pm

Thanks a lot! Now I need to get to work!


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Re: Reverse Flow Smoker

Post by Rodcrafter » February 25th, 2018, 9:42 am

But you can know it will work right when you’re done.


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Re: Reverse Flow Smoker

Post by forty_creek » February 25th, 2018, 9:28 pm

Ditto what these pros are telling you! Once it’s right a split or 2 every 45-60 mins is dead on, even for a 500 gal RF...

These guys are pros!


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