Need some advice from the pros on exhaust size.

[dtel]

Sorry, long trying to explain my confusion...
Building an offset smoker from a propane tank, it is 24" deep and 44" long, firebox is 24" round and 19" long.
I have used the Feldon calculator in the past with good results but the problem I am having is exhaust. The smoker has the firebox in the center rear with diffusers and I wanted an exhaust on each end. The calculator only shows for one exhaust size and length.
I have some 3.5id and 4" id pipe. 2 3.5 id pipes equals one 4.95inch id but how do I figure out length it says 20.75 length for a 5" and I probably just can't cut that in half ? 2@ 11" don't think it works like that?

Hard to explain, I only built it like this because my old now burned out smoker was center/rear fed with an exhaust on each end and is very evenly heated.

Got the calculator from a website I was on years ago and it is now gone and this site looks really good for questions about builds and recipes and much more.

Thanks

 

[Winterrider]

Snoop around in this thread, might find some help. Dave was top notch at this type of info. Good luck . . .

Standard Reverse Flow Smoker Calculator... by DaveOmak and others... Ready to use.. rev5.. 6/19/15.

Here's to "Alien BBQ" and the folks that first put the calculator together and "1728 Software Systems" for this great "Circle Calculator" and all the folks at "SmokingMeatForums", with a special shout out to Ribwizzard, that contributed their ideas and feedback while this thing was coming...

www.smokingmeatforums.com

 

[dtel]

Wow there is alot there, I need to start reading it and try to figure it out.

Great place to start, THANK YOU.

 

[dtel]

I know pictures help so I will try to add a couple, 44" long 24" deep and 1/4" thick. Just starting out firebox mounted and door cut. Welding is not pretty but I am old and not so great eyes but it will do.

 

[philpom]

The calculators spec the stack partially on the volume of the smoker but height is probably more important for good draft than volume of the stack. I'd keep each stack close to the calculator height. You might get away with a little bit shorter but best to install them tall, test, and shorten if needed. Easier to remove height than add it.

Sounds like a cool design, good luck!

 

[1MoreFord]

Sorry, long trying to explain my confusion...
Building an offset smoker from a propane tank, it is 24" deep and 44" long, firebox is 24" round and 19" long.
I have used the Feldon calculator in the past with good results but the problem I am having is exhaust. The smoker has the firebox in the center rear with diffusers and I wanted an exhaust on each end. The calculator only shows for one exhaust size and length.
I have some 3.5id and 4" id pipe. 2 3.5 id pipes equals one 4.95inch id but how do I figure out length it says 20.75 length for a 5" and I probably just can't cut that in half ? 2@ 11" don't think it works like that?

Hard to explain, I only built it like this because my old now burned out smoker was center/rear fed with an exhaust on each end and is very evenly heated.

Got the calculator from a website I was on years ago and it is now gone and this site looks really good for questions about builds and recipes and much more.

Thanks

If you need 21" of 5" pipe, then use 2- 21" long 3.5" pipes to give you the same volume as 1- 5" pipe.

 

[dtel]

That's what I was thinking but thought it would be smart to ask. Thanks

 

[dtel]

Exactly, I can always cut it off. That would give me roughly the same cubic inches of exhaust as a single 5".

Thank You

 

[dtel]

This kind of help is exactly why I came here, besides a ton of ideas on cooking and many other things, this is a pretty large site which helps when needing advice.

Thanks for the help, and a really nice site for ideas and help.