Firebox questions

[jrgreene1968]

I’ve got a few questions on a firebox, wandering if y’all could help me. My old smoker is on its last leg, and I’ve been wanting a bigger one anyway, so kinda been on the lookout for the pieces to get started. Today I scored a 125 gallon tank that’s 24” od, and some 20” pipe.
My thinking is use the 20” pipe for the firebox. Wandering if I would be better off using plate steel for the firebox, or would the pipe work ok? It is 1/4” wall. Reason I ask, is most of the smokers I’ve been looking at seem to have square fireboxes, I figure there’s a reason.
2nd question.. how critical is it when sizing the firebox using the calculator? I’m coming up with around 130% using the dimensions I’d like to use, do I could burn longer wood.
I’m sure I’ll be asking a ton more stupid questions, as this is the first smoker I’ve built. Would love to just go buy a new gator etc, but when I even mention it, the wife starts giving me the side eye
Thanks

[Dirtytires]

Round is fine but I definitely prefer to use plate for my firebox. You can work all the dimensions so that it sits properly, allows length for your logs and is sized properly. The square box is also easier to work with...such things as air vents, hinges, doors and log racks are always easier to fit to a flat surface.

Yes, size is important. I believe the current recommendation is to make firebox 110%....somebody correct me if I’m off.

[jrgreene1968]

Thanks for the reply. Well I may end up having to use plate steel, since I can’t get the correct firebox size % with the pipe.
Looks like I’m gonna be buying me a metal cutting circular saw for the plate then...I can’t cut straight with a torch, lol. Good excuse to buy one.. been wanting one anyway
Thanks

[jadstar]

They make metal cutting blades for Standard 7 1/4" circular saw . Having said that it will need to be one with steel or Aluminum dust chute or things will go south quick! These blades are usually less than 10 bucks and cut a straight line just go slow and let it eat .

Sent from my Moto Z (2) using Tapatalk

[jrgreene1968]

They make metal cutting blades for Standard 7 1/4" circular saw . Having said that it will need to be one with steel or Aluminum dust chute or things will go south quick! These blades are usually less than 10 bucks and cut a straight line just go slow and let it eat .

Sent from my Moto Z (2) using Tapatalk

Thanks buddy.. I went ahead and ordered a new Milwaukee 8” saw. Been wanting one anyway.
I do have another dumb question though.
I’ve got a smoker at my shop that needs a new firebox on it, and after getting the old firebox cut off, the throat is shaped like a football, where they overlapped the fb and cc.
I’m trying to wrap my head around this, to make that throat shape work with a square firebox. I can weld in a flat bar on the bottom of throat, to get a grease dam.. which will then give me a half moon shape, but it will be upside down half moon. Does that matter?
Thanks

[Dirtytires]

The joy of a flat firebox is that the throat can be cut in any shape to match the cook chamber. Shape doesn’t really matter as long as it’s of the correct size....be sure to double check it and not rely on the original builder to have gotten it correct.

The that said, make sure the grease dam does not block the throat....

[Brisket Envy]

How long is the firewood you want to use?
A 125 gallon tank would require something in the neighborhood of a 32” piece of 20” pipe.

[Dirtytires]

I get my firewood already cut/split. It is 18-20 inch long, on average. I leave the length but always split each piece till I get them about 3–4 inch in diameter...about the diameter of a soda can.