First Smoker build

[Sven556]

I recently found a couple pieces of 15" ID metal both 3/8" wall. One is pipe 31" long and the other is cast iron or cast steel 22" long. Now I know these will make a small smoker compared to most of you! I rarely cook more than one or two butts or one brisket at a time. Right now I have a traeger Junior and find it adequate size wise but, I would like to use charcoal and wood or preferably just wood, at times. I would like to build either a smoker or bbq. I am currently leaning towards a reverse flow smoker, but feel free to suggest other ideas. I went through the calculations, for a reverse flow, in the first post and these are what I came up with:

Internal volume of CC = 15" diameter x 31" length = 5478 in^3
Internal volume in gal = 23.715 gal
FB/CC opening = 21.912 in^2 => add 25% for small patio type smoker = 27.39 in^2
Firebox air inlets = 5.478 in^2 split 80% lower and 20% upper
Area under RF plate and Area at end of RF plate =27.39 in^2
Exhaust stack volume = 120.5 in^2
2.25" ID pipe would give 143.13 in^2 at 36" length
ED =3.25"
chord AB = 12.359"

Fire box volume
Min = 1807 in^3
16" length of firebox gives 3.14 x 7.5"^2 x16 = 2827 in^3
2827/1807 = 156%

Anyone see any errors in my calculations? Or have experience to share with a small smoker such as this? I haven't found much info on making a small reverse flow unit. Would there be any negatives to making the firebox even bigger? I generally cut firewood at 16" lengths so that would be handy to keep all logs the same length, but not a deal breaker by any means.

 

[busmania]

I built a small one out of a 33 gallon compressor. I think it is similar to your dimensions but maybe 18” wide. Long story short, it was sensitive. I think my problem has always been (now that Ive used a larger smoker and looking back on this build) too big of a fire. I no longer use it and it sits on the side of my house. I ended up buying a Yoder whichita (40’ish inched by 20”) and haven’t looked back. That Home build was finiky. Some day I’ll make some improvements but for now it sits depressed, stripped down and dusting on the side of my house.

I know you can make your smaller one work. Just my personal thoughts.

My build.
https://www.smokingmeatforums.com/threads/my-first-build-help-me-please-reverse-flow.181548/

 

[daveomak]

Area under RF plate and Area at end of RF plate =27.39 in^2
Exhaust stack volume = 120.5 in^2
2.25" ID pipe would give 143.13 in^2 at 36" length
ED =3.25"
chord AB = 12.359"

When building a "small smoker", the surface area to volume increases friction... increase those numbers to get a better performing smoker... How much?? Don't know for sure, but, an increase is necessary for performance....
One member made an RF smoker out of a SCUBA cylinder....

https://www.smokingmeatforums.com/threads/scuba-tank-mini-reverse-flow-first-build.138246/

 

[weedeater]

Sven556,
Look up posts by “Ribwizzard” in the search function. He has built and posted a lot of builds of smaller patio size reverse flow smokers. Haven’t seen him on the site much in a long time but his post are still here and should provide you a wealth of information.

Weedeater