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Double check before build

Rod630

Newbie
3
1
Joined Oct 7, 2020
I am getting ready to build a trailer smoker, this is my first build so I want it to be correct. I have done some research and would like someone whos done a build to double check before I proceed with fabrication. Below is what I have came up with using the feldon calculator. This will be a reverse flow. If anyone has some good links to builds or has any good advise to give would be greatly appreciated!

-CC dimensions=33" dia.x 72" L.
-FB dimensions=26"H x 33"W x 24"L
-Chimney= 6" pipe x 36.43" Long
-Intake= 6" length x 1", (10-11 needed)
-FB/CC opening= 20.48" half moon
(164.74sq.in.)
-Would a round firebox box be more efficient than a square or rectangle one?
-How high should the baffle plate be above the firebox opening?
-What would be an acceptable height between the baffle plate and cook grate?

TIA- Rod-
 

Rod630

Newbie
Thread starter
3
1
Joined Oct 7, 2020

Big Bad Wolf

Newbie
13
6
Joined Jul 31, 2022
I am getting ready to build a trailer smoker, this is my first build so I want it to be correct. I have done some research and would like someone whos done a build to double check before I proceed with fabrication. Below is what I have came up with using the feldon calculator. This will be a reverse flow. If anyone has some good links to builds or has any good advise to give would be greatly appreciated!

-CC dimensions=33" dia.x 72" L.
-FB dimensions=26"H x 33"W x 24"L
-Chimney= 6" pipe x 36.43" Long
-Intake= 6" length x 1", (10-11 needed)
-FB/CC opening= 20.48" half moon
(164.74sq.in.)
-Would a round firebox box be more efficient than a square or rectangle one?
-How high should the baffle plate be above the firebox opening?
-What would be an acceptable height between the baffle plate and cook grate?

TIA- Rod-
Your reverse flow cooker is nearly the same size as mine. Mine has a 36" dia. cook chamber x 60" lg. The total internal dims of both are nearly the same. To answer a few of your ?? I would make a rectangle firebox at .333 the size of the cubic inches of your cook chamber. The size you have listed is close to what you need. The baffle plate should be at the top of your firebox to cook chamber opening....it's just a continuation of the top of your firebox. The top of my lower grate is 4" above the 1/4" baffle plate and seems to work great. You will need about 62 square inches of air inlet openings on your firebox. The majority of air inlet openings need to be below your fire and the remainder in line with your opening from the firebox to cook chamber. The ratio is about 80% below fire and 20% in line with your firebox to cc opening. The length of your exhaust stack needs to be calculated above the top of the cook chamber. I have pictures posted here of mine. Maybe will give you a few ideas. Big Bad Wolf.
 

Rod630

Newbie
Thread starter
3
1
Joined Oct 7, 2020
Your reverse flow cooker is nearly the same size as mine. Mine has a 36" dia. cook chamber x 60" lg. The total internal dims of both are nearly the same. To answer a few of your ?? I would make a rectangle firebox at .333 the size of the cubic inches of your cook chamber. The size you have listed is close to what you need. The baffle plate should be at the top of your firebox to cook chamber opening....it's just a continuation of the top of your firebox. The top of my lower grate is 4" above the 1/4" baffle plate and seems to work great. You will need about 62 square inches of air inlet openings on your firebox. The majority of air inlet openings need to be below your fire and the remainder in line with your opening from the firebox to cook chamber. The ratio is about 80% below fire and 20% in line with your firebox to cc opening. The length of your exhaust stack needs to be calculated above the top of the cook chamber. I have pictures posted here of mine. Maybe will give you a few ideas. Big Bad Wolf.
Your reverse flow cooker is nearly the same size as mine. Mine has a 36" dia. cook chamber x 60" lg. The total internal dims of both are nearly the same. To answer a few of your ?? I would make a rectangle firebox at .333 the size of the cubic inches of your cook chamber. The size you have listed is close to what you need. The baffle plate should be at the top of your firebox to cook chamber opening....it's just a continuation of the top of your firebox. The top of my lower grate is 4" above the 1/4" baffle plate and seems to work great. You will need about 62 square inches of air inlet openings on your firebox. The majority of air inlet openings need to be below your fire and the remainder in line with your opening from the firebox to cook chamber. The ratio is about 80% below fire and 20% in line with your firebox to cc opening. The length of your exhaust stack needs to be calculated above the top of the cook chamber. I have pictures posted here of mine. Maybe will give you a few ideas. Big Bad Wolf.
To this point, the only question I had was the stack height and where that measurement was pulled from and you confirmed what I thought as I had misunderstood that to begin with. Luckily I'm not to that point quite yet. Thank you for your reply! Pictured is what I got so far and all the info you provided is spot on with what I have currently. Trying to find time after work to work on it has been the biggest challenge so far!
 

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Big Bad Wolf

Newbie
13
6
Joined Jul 31, 2022
To this point, the only question I had was the stack height and where that measurement was pulled from and you confirmed what I thought as I had misunderstood that to begin with. Luckily I'm not to that point quite yet. Thank you for your reply! Pictured is what I got so far and all the info you provided is spot on with what I have currently. Trying to find time after work to work on it has been the biggest challenge so far!
Looks like it is coming together nicely. I used a 7" dia. stack and I think it is 35" above the cook chamber. I built a plenum and mounted mine on the end above the firebox. Have two pullout grates in mine and can easily cook 24 - 28 Boston Butts with no problem. Just make sure the openings for your air flow are adequate between the firebox/cc and at the end of the reverse flow plate. they should be the same size in square inches. Mine holds even temps end to end within about 5 degrees with the door dial thermometers. I also use the Thermoworks Smoke readout for meat temp and cc temp.
 

Big Bad Wolf

Newbie
13
6
Joined Jul 31, 2022
I am getting ready to build a trailer smoker, this is my first build so I want it to be correct. I have done some research and would like someone whos done a build to double check before I proceed with fabrication. Below is what I have came up with using the feldon calculator. This will be a reverse flow. If anyone has some good links to builds or has any good advise to give would be greatly appreciated!

-CC dimensions=33" dia.x 72" L.
-FB dimensions=26"H x 33"W x 24"L
-Chimney= 6" pipe x 36.43" Long
-Intake= 6" length x 1", (10-11 needed)
-FB/CC opening= 20.48" half moon
(164.74sq.in.)
-Would a round firebox box be more efficient than a square or rectangle one?
-How high should the baffle plate be above the firebox opening?
-What would be an acceptable height between the baffle plate and cook grate?

TIA- Rod-
I did some quick calculations on your unit. You have 61,581 cu. in. in your cook chamber. The recommendations on a reverse flow are cooking chamber cu. in. x .022 for the exhaust stack cu. in. All exhaust stack lengths are figured above the top of the cook chamber. You could use a 6" inside dia. pipe but should be 48" above the top of the cook chamber, or a 7" inside dia. pipe x 36" above the top of the cook chamber. Either will work. Since you already have 6" pipe I would use it but make it 48" above the top of the cook chamber.
 

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