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500 gallon build

lonewolf3762

Newbie
10
2
Joined Jan 24, 2021
Hello all. I’m going to build a 500 gallon Reverse Flow smoker .... I would like information from those of you who have done so, successfully.
Currently, my tank is 108 inches long and a diameter of 34 inches.
I would like 2 racks (full length) so I can cook whole hogs in summer (only using one rack) and turkeys (2 racks) in the winter.
I will need to reach a chamber temperature of 350-375 ideally for the turkeys, so that’s the temperature I need to achieve.
What is the ideal height and width of the throat plate (baffle plate) along with the length,? What size (dimensions please) shall I build my firebox? I’ve got access to a 10” and 8” diameter pipe for exhaust.
Please don’t refer me to “build calculators”, I’ve been struggling with understanding some of them.
 

smokin peachey

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Are you dead set on reverse flow? I built a smoker out of a 500 gallon tank but didn’t go reverse flow. My doors are designed so you could easily do a whole hog.
 

lonewolf3762

Newbie
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2
Joined Jan 24, 2021
I’d prefer reverse flow... my understanding is it gives a more even cook when doing 200+ pound hogs.
I am open to discussing an offset smoker though. Knowledge is power.
 

smokin peachey

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Have you tried the search function here looking for threads with similar builds?
 

gary s

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Hello and Welcome from East Texas
Can't wait to see pics

Gary
 

lonewolf3762

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Joined Jan 24, 2021
Hello and Welcome from East Texas
Can't wait to see pics

Gary
Hello Gary. Greetings to Texas from Utah. I’ve seen your name on several build posts, you’ve given tons of great information to help people with their builds. I’m hoping you can answer some questions that I’ve encountered along my journey of this build..... number one question pertains to the firebox - according to multiple pit calculators, my FB will be HUGE to meet the recommended (33%) size of cool chamber. How accurate are the calculators when it comes to those numbers?
 

lonewolf3762

Newbie
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Joined Jan 24, 2021
I’ve already got my tank cut, I cut one end off to give me a square flat end to work with for my FB and Warmer. So my tank is 34” diameter and 108” long. Giving a Cook Chamber of 98000 cu in, and a recommendation FB of 33000 cu. HUGE FB!!! My current FB measures 21” tall, 28” wide, and 28”’deep.... only giving 16000 cu in (50%) of recommended FB size. That’s a lot of weight hanging off the end of the CC, especially if I make the FB even larger.
Currently the FB is attached to CC, with a half moon opening, 29 inches wide and 8 inches at highest point...... a door opening (2 doors) at 17” wide 13” tall, and two 4” x 4” air vents / one on each side. I also have a wood rack inside of FB, sitting 2” off the bottom.
Baffle Plate (BP) is 96” long, starting at 28.5” wide at 8” from bottom of CC.... tapering down to 26.5” wide and 6” from bottom of tank.
Exhaust is a 10” pipe at 17” length - it’s what I had available without purchasing a 8” pipe.

Current setup did get CC to 300 degrees, but FB was showing 600-700 degrees at that time, and adding multiple pieces of wood every 10 minutes. Obviously this is not efficient nor are things working correctly.

Any advice on correcting things and the correct measurements for BP, FB to CC opening, or anything is EXTREMELY APPRECIATED.
 

gary s

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How about the F B Door vents how big ? Does or will the CC get hotter if you leave the door cracked ?
Also a little confused, you said your FB was 28" wide but your FB to CC opening was 29" wide?

Gary
 
Last edited:

lonewolf3762

Newbie
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Joined Jan 24, 2021
I use one door as a vent. I keep it open 2-3 inches and that’s where I achieve 300 degrees. If I close it completely, the temp drops and I get dirty smoke. If open completely, temp only hits 250-270
 

gary s

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Send me some Pics so I can get a better idea

Gary
 

lonewolf3762

Newbie
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2
Joined Jan 24, 2021
I will get more photos after work. These will hopefully get you a better idea
How about the F B Door vents how big ? Does or will the CC get hotter if you leave the door cracked ?
Also a little confused, you said your FB was 28" wide but your FB to CC opening was 29" wide?

Gary
It’s been a couple late nights at work, I apologize for the delayed response. I’ll be out of town until Saturday morning, so better pictures will have to wait until then.
The FB is 28 inches wide, and I had a poor measurement that caused me to cut the opening at 29”.... I filled in the extra gap so that there is no airflow escaping in the extra space.

The main concern is the actual size of FB I may need. If I extend the current one, the extra welds will make it look ugly.... I do have a lead on a 125 gallon propane tank for $40... that will be 85% the “recommended” FB size. - I’m keeping it as an option, as well as making it a smaller smoker.
 

Ranch House

Newbie
SMF Premier Member
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36
Joined Nov 27, 2020
Hello all. I’m going to build a 500 gallon Reverse Flow smoker .... I would like information from those of you who have done so, successfully.
Currently, my tank is 108 inches long and a diameter of 34 inches.
I would like 2 racks (full length) so I can cook whole hogs in summer (only using one rack) and turkeys (2 racks) in the winter.
I will need to reach a chamber temperature of 350-375 ideally for the turkeys, so that’s the temperature I need to achieve.
What is the ideal height and width of the throat plate (baffle plate) along with the length,? What size (dimensions please) shall I build my firebox? I’ve got access to a 10” and 8” diameter pipe for exhaust.
Please don’t refer me to “build calculators”, I’ve been struggling with understanding some of them.
Gary this is not a reverse flow and it's not set up for hogs but the heat flow is very consistent across the racks. FB is 30" outside 24" inside 44" long with 3" of insulation. I do have a short heat deflector in the cook chamber. FB to CC open in is half moon close 1/3 of the 24" pipe top is at bottom rack level. I used a 10" stack. I'm building a rotisserie now and have another 500 gallon tank I'm going to build a hog cooker out of like this off set other than the doors and racks will be different. I'm going to try to build my bottom rack so it will slide out and have a pivot so you can rotate it easy. This is just an idea on the rack I haven't layed one out to see if it will work. If you build an offset my advice would be to use multiple pieces of plate instead of one solid piece you can slide them around or open a little gap if needed to direct your heat they basically can be used for tunning plates.
 

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kmmamm

Meat Mopper
224
81
Joined Apr 30, 2016
Ok , so if I am reading your dimensions correctly, the rf plate is setting on the top of your fb opening (8” off the bottom of the tank) and it tapers down and terminates 6” off the bottom of the cc. If that is correct, the area of the opening at the end of the rf is effectively smaller than the opening between the fb and cc thus creating a choke point in the air flow. You might try orienting The cooker so that the fire box is setting downhill (jacks, blocks, parking it on an incline, etc) and see if that improves the draft. If it does, then you will need to do some experimenting to find the incline that best balances draft and even cc temps .
good luck
 
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lonewolf3762

Newbie
10
2
Joined Jan 24, 2021
Originally the FB to CC opening was 11 inches from bottom of CC... and did taper down to 9 inches - I wanted to create a grease drain so the smoker would still sit level....
The CC would reach 350, but I had to get the FB to nearly 700 degrees to accomplish that temperature. That put the RF plate high enough that I couldn’t put the rack as low as desired for a whole hog.
So now I’ve dropped things lower and still need to get FB to 700 in order to get CC to 300-325.

Maybe I’ve got the wrong expectation, but I didn’t think I’d need to get the FB that hot in order to get the CC to 300+ degrees. I know a 500 gallon tank is a large amount of steel to heat up, and it will take a lot of heat to do so....

I’m just asking if anyone has built one with a tank diameter of 34”.... and if they can help point me in the right direction. I have found a 125 gallon propane tank I can use as the FB, which would put me at 87% of recommended FB size for this CC volume.
 

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Weaversbbq

Newbie
28
10
Joined Jan 26, 2021
Hello all. I’m going to build a 500 gallon Reverse Flow smoker .... I would like information from those of you who have done so, successfully.
Currently, my tank is 108 inches long and a diameter of 34 inches.
I would like 2 racks (full length) so I can cook whole hogs in summer (only using one rack) and turkeys (2 racks) in the winter.
I will need to reach a chamber temperature of 350-375 ideally for the turkeys, so that’s the temperature I need to achieve.
What is the ideal height and width of the throat plate (baffle plate) along with the length,? What size (dimensions please) shall I build my firebox? I’ve got access to a 10” and 8” diameter pipe for exhaust.
Please don’t refer me to “build calculators”, I’ve been struggling with understanding some of them.
Why reverse flow?
 

lonewolf3762

Newbie
10
2
Joined Jan 24, 2021
Why reverse flow?
I don’t have a way to spin my rack when I’m cooking whole hogs... reverse flow doesn’t allow as much chance to burn one end of the meat. Reverse flow doesn’t use as much wood as an offset smoker (of this size) will. And I prefer the look/challenge of the reverse flow.

I will build an offset this summer for backyard use.
 

kmmamm

Meat Mopper
224
81
Joined Apr 30, 2016
I size the firebox a minimum of 15-24% larger than the Feldon’s calculator value and size the total area of the adjustable combustion inlets and exhaust stack 5-10% larger than the calculator. I divide the inlet air openings into three separate inlets and orient on the door so that one is at or below the fire grate and the remaining two are located at or just below the door’s mid point. Not sure if it is the perfect solution, but it produces clean smoke with the door closed, using only the inlet vents to adjust combustion air.
target average cc temps between 240 and 275 for long and slow cooks, but the system is fully capable of cc temps in the 400-450 range (think vegetables, sides, etc) and will run 500+ if the inlet vents are fully opened and there are sufficient coals in the fb.
Don’t get hung up on the temperature difference between the fb and cc, instead focus on the volume equation.
 

lonewolf3762

Newbie
10
2
Joined Jan 24, 2021
I size the firebox a minimum of 15-24% larger than the Feldon’s calculator value and size the total area of the adjustable combustion inlets and exhaust stack 5-10% larger than the calculator. I divide the inlet air openings into three separate inlets and orient on the door so that one is at or below the fire grate and the remaining two are located at or just below the door’s mid point. Not sure if it is the perfect solution, but it produces clean smoke with the door closed, using only the inlet vents to adjust combustion air.
target average cc temps between 240 and 275 for long and slow cooks, but the system is fully capable of cc temps in the 400-450 range (think vegetables, sides, etc) and will run 500+ if the inlet vents are fully opened and there are sufficient coals in the fb.
Don’t get hung up on the temperature difference between the fb and cc, instead focus on the volume equation.
Thank you for the information. I will likely change my FB to the 125 gallon tank, which will increase the size of FB.
Will likely be out of town next weekend so it’s going to be a couple weeks until I get things switched over. Please continue to provide information as you learn your system and setup. Thanks
 

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