200 Gal reverse flow

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mose99

Newbie
Original poster
Dec 22, 2024
3
2
Hello all,

This is both my first post and my first smoker build.
My current plan is to build a reverse flow smoker using an old furnace oil tank (cleaned out of course). Here is the link to what originally inspired me...


My tank is a 200 gal size (the same style as the one linked above)

Browsing the forums I used the calculator (will attach a image of my calculations). I also did some digging for inspiration/ideas regarding the baffle.
On this forum I really like cjohnson3006 & fatbastard09's design with the cement instead of a waterpan.
Are there any negatives to going that route other then weight/cost?
I am from Canada so having the large heat sink in there to maintain temps in the winter would be a benefit, along with not having to worry about the waterpan freezing).

Here are some pics of the initial burn to get any oil residue out. (Had the top and sides glowing lol).
burning residue out 2.jpg
burning residue out 1.jpg


Here are my calculations. If anyone see ay issues with them let me know. I took daveomak's math and put it into excel so I can easily adjust numbers if things change.
I'd love to put a cold smoke chamber in place of a smoke stack.
However, that will depend on the temperature of the smoke when it exits... may be a upgrade later.
calculations.png


Once the fire is burned down, I will cut my holes for the firebox and smoke stack. Then start mocking up how its going to fit on the trailer.
One question I did have was related to firebox dimensions.
I know its better to have a tall firebox (to help with smoke draw).
However, does length/width have the same affect? or is it all related to how big a piece of wood I want to use?

Thanks!
 
So update to the plan... it has changed slightly... here's the Kole's notes for those that don't want to read.

  1. The tank is 240 US gal. That was a mistake on my part. The tank is 200 Imp gallons.
  2. Due to the abundance of old furnace tanks I've decided to use a second one of those opposed to designing/building a firebox.
  3. I cut 2 of the feet off and rewelded them on the same side to give me a nice easy mounting solution later.
Obviously the first issue matters as it throws off all the dimensions. The good news is I was using solid works to lay everything out and it tipped me off that the tank size was wrong. (layout seen below).
smoker layour Rev001.png


The second part is using the second tank as a firebox. This was decided due to the oval shape of the cook chamber, along with cost.
The tank was free, the right radius and makes it really easy to get the 1/3 of the cook chamber size. my tank is 60.5" end to end, divide by 3 to get 20 1/8".
I just cut 1/3rd off the second tank and I'm good to go.
From there I will measure/draw a line at my 6.5" mark, line the tanks up how I like and cut/weld them together. (see pic of todays mockup).
f5666c98-79dc-43fd-959c-5f76da79a35d.jpg

cb1b73e3-ae54-48e5-b8ff-c393cb7abb65.jpg

Ignore how crooked the cut is LOL, I was in a hurry to get the pic because it was raining.

last thing is a picture of redoing the feet...
d8b56b5f-000d-4889-8b94-64ee13198793.jpg


I need to do some research into how much overlap people run on their smokers (I was thinking 1-2"). However, I'm worried about how the overlap would affect temps right at the opening?
Would it be better to do that or just butt them together?

Thanks!
 
Cannot help you on the calculations for an offset.

Nice idea for a build.
I've seen cookers and smokers made from old fuel oil tanks. They're 275 - 300 gal in the US. Never saw an offset. They were either very large horizontal charcoal grills or vertical indirect hog roasters.
The metal is very thin to burn anything fuel directly on it. All have had trays or baskets to hold and load fuel which is usually charcoal and wood chunks.
 
Yea, its big enough I struggle to move it around lol. The cook grate will be a slide out style so you can actually use the back of the smoker.

My next hurdle will be either building or repurposing a trailer to mount it on. That should make all my cutting/welding much easier.

The metal is thin (12 gauge). This wont be a huge issue for the cook chamber itself (aside from efficiency).
To deal with that for the fire box my current plan is to support it with additional steel from underneath probably tying into the tank "legs" and the firebox itself will be lined with firebrick to help with heat retention. I do plan on running a grate of some kind so the fire is above my lower air inlet, and to make cleaning easier. I also want the top of the firebox to double as a cook top for a pot or frying pan. So I'll probably add some 1/4" plate with stove eyes cut into it for that purpose.

The open end of the firebox tank will be the end that the door goes onto. My plan for that is to use a piece of 1/4" steel cut to the right shape then pull it together and weld it on (have to design that yet).
 
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