60 gallon air tank build

Discussion in 'Reverse Flow' started by mburgess00, Dec 23, 2015.

  1. I just acquired a 60 gallon air tank and am going to document my build here. Does anybody care to double-check my calculations?

    Here's what I have so far:

    The tank is 20" in diameter. The length of the tank is 37" weld to weld. The rounded end caps are about 6" each, for a total of 49" (approximately). Given that it's 60 gallons, it's 13860 in^3 in volume.

    The FB/CC opening, area under RF plate, and area at the end of the RF plate will need to be at least 55.44 in^2. To achieve this, the inside of the firebox top will be at 5" from the bottom of the tank. This will provide 61 in^2 of area.

    The FB needs to be at least 4573.8 in^3. I am planning a 20x18x18 outside dimensions firebox for a total of 5971.871 in^3.

    FB air inlet needs to be at least 13.86 in^2.

    Exhaust needs to be at least 305 in^3. I plan on going with 36" of 3.5" i.d. pipe for 346 in^3.

    Here's a diagram I drew up to scale. Comments enthusiastically welcome!

  2. Based on the dimensions given and my build experience with 7 reverse flow builds, I would probably go with 4" exhaust pipe for a shorter overall height.
    Aesthetically speaking and for overall performance, I've noticed if your exhaust is much more than the cook chambers diameter it tends to cool the exhaust gases and will effect the overall airflow.
    Just my $0.02
  3. Great comments on the exhaust. What do you think the length should be with that diameter? I had read elsewhere to consider a minimum of 36".

    Based on the availability of used steel I could find, I am thinking about a firebox 12" wide (see drawing below). Does anybody think I will run into any issues with this shape?

  4. The appearance of a smoker is a huge part of the build process for me, so with that said I wouldn't build it with a width less than the diameter of the tank in this case 20"

    In your drawing above you referenced 12"depth and the only potential issue I foresee would be the heat control ability you'll loose with a shallow firebox. If you build the firebox 20"W x 18"L x 18"H you'll maintain the ability to slide a wood box further in for more heat on the firebox side or closer to the door for less.

    I'll post my recommendations for all your measurements in another post this afternoon.
  5. So here's how I would build it.

    Firebox 20"W x 18"L x 18"H
    Exhaust 4" x 26"
    Intake 3" x 8" (1)
    The firebox cutout on the cook chamber would be 6.5" up and 7" (or to the weld seam) in from the end ( let me know if there is a huge difference in the 7" or the location of the weld seam, probably isn't )
    The cutout in the firebox would be a half moon 5.75" tall centered on the firebox.
    Let me know if you have any more questions.
    I'll help anywhere I can.
  6. Thanks very much for the reply. After living with it in drawing form for a while you are definitely right. That skinny would look really strange. Otherwise your numbers agree with mine so that's good.


  7. Any updates on your build, pics are good it's how I get new ideas
  8. Along with finding some good steel at the scrap yard and getting got some time to work on this project, I present the (mostly) completed build. Obviously it still needs a door handle, a coat of paint, and a storage cap for the chimney.

    A couple of observations from the initial burn-in/test:

    1. I am wondering if my top vent is too high. When I open it, smoke seems to come out rather than providing extra air into the cook chamber. As you can see from the layout lines, I had planned a middle vent that I think I will go ahead and add.

    2. Temps from left to right were pretty different (75* or more). This may actually not be a bad thing, just something to be aware of. 

    3. I was pretty impressed with how well it held temps and how easy adjustment was. This thing performs much differently than the COS and UDS that I've had before.

    Let me know if you guys want any close-up pics of anything.
  9. Some finishing touches including paint, handle, and a mid vent.

    Last edited: Mar 2, 2017

Share This Page