My first build

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Original poster
Dec 13, 2013
Martinsville Va.

I am building a reverse flow smoker out of a propane tank I need help with the measurement. How big of a fire box do I need I was thinking about useing a tow motor tank but don't know if it will be the right size. Where do I put the baffle I was thinking about cutting a 3 or 4 inch pipe in half and weld it in the middle of the baffle plate and make a trough for the drippings to drain to the drip tube. How big should the opening be at the fire box and at the other end for the smoke to go in the cooking chamber. What size of pipe should I use for my smoke stack and how long should it be? The tank is 73" long and 132" round. I was going with one door but also was thinking I might put one one both sides. I want a lower and upper cooking racks.
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WOW......... What a great tank for a smoker...... Fat and short.... PERFECT..... wish I could find one like that.... Lots of rack room for lots of meat.... Perfect for putting doors on each side for easy access.. You are very lucky to find such a jewel.....

Don't blow yourself up cleaning it out.... Do not cut into it until you have all your dimensions figured out... Check with folks here for great ideas....

That is a really cool tank to start with! I'll be watching this. As far as fire box size, I would plug those numbers into a pit calculator to get you close. I usually go a little bigger because I'm up in Michigan, and I like to smoke year round. 
Thanks Dave,
I work for a propane company. I asked my boss if I could get an old scrap tank I was thinking about one of our 500 gal tanks but he said for me to get this one and it was free. Yea I know I have to fill it with water to get it flushed out. I was told that it helps to put some dish washing liquid and put in it to
Qwikrnu BBQ I plan on smoking year round although it doesn't get as cold here in Virginia but I think I'll go with a little bigger fire box too
This is the one he would let me have there is pros and cons to both I'm sure. It will take up less space on the trailer I'm going to build. I am fixing up two burners so I can cook onion rings, french fries, hush puppys and fry chicken. I probably will get a 500 later on.
I used the calculator from
My phone would not let me copy and paste my figures so I'm going to put it on here myself.
Cook chamber 132" diameter 73" length cook chamber size 998482.32 recommend firebox size 332827.44
Firebox dimension (square) height 21" wide 21" length 24"
Specified firebox size 10584.00
recommend firebox size 332827.44
Chimney pipe size 4"
Recommend chimney volume 529.20
Length of chimney 42.13"
Firebox intake (square) length 6"width 6"
recommend air inlet 31.75 square inch number of intakes. 88
firebox -to- cook chamber opening size
Round 10.39"
Half moon 14.68"
recommend firebox - to - Cooker opening area 84.67
Howdy, Smoke. I think you have the diameter of your tank wrong. 132" diameter would make it 11 feet tall. Did you by chance measure the circumference around it instead? The diameter should be the width of it, probably 30 something inches. Most of the other calculations in the calculator come from the size of the firebox, not the cooking chamber. Check your number and plug it back into the calculator.

Thanks Keith and yes that's what I did. I
misunderstood how to get the measurement. I put a pic of the ID tag and it says the diameter is 41" so I will go back and redo it
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