Firebox to cooking chamber opening

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MikeT
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Firebox to cooking chamber opening

Postby MikeT » Tue Aug 21, 2018 5:32 am

Hi! I’m new to this forum.
I am planning a 24”x 24” x60” rectangular cooking chamber with a 24” square firebox. I’d like to make it traditional as well as reverse flow by adding plates. I will have dampers. H
How large should my opening be where I attach the firebox to the smoker? 24w x how tall? In other words, where should I position my firebox?I’ve built pits a long time ago and pretty much guessed at it. I’ve always used pipe or something cylindrical but thinking about changing things up for this one.
I would appreciate any thoughts.
Mike
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PinoyPitmaster
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Re: Firebox to cooking chamber opening

Postby PinoyPitmaster » Tue Aug 21, 2018 9:41 pm

Search this site for “Feldons Calculator”. It will give you your answer and more.


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Re: Firebox to cooking chamber opening

Postby Garrett32 » Wed Aug 22, 2018 8:25 pm

I’m needing help on fire box to grill opening I have a piece of 24”by60 pipe an square fire box
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Re: Firebox to cooking chamber opening

Postby Garrett32 » Wed Aug 22, 2018 8:35 pm

I’m needing help on fire box to grill opening I have a piece of 24”by60 pipe an square fire box
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Re: Firebox to cooking chamber opening

Postby Copasspupil » Thu Aug 23, 2018 9:33 am

First did you look at his link? You have to calculate the opening based on area you firebox and cooking section. Yes yours is rectangular and square but the principles are still the same.

From the link you need to figure out the exhaust pipe size and how large of the fresh air opening you will need for the fire box.
Danno

'66 GT350S clone
Custom built smoker named Seal Team
Santa Maria Grill names GrumpyD'sBBQ
Weber stainless gas grill when I want to cook a hotdog
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Re: Firebox to cooking chamber opening

Postby SmohhkyD » Thu Sep 13, 2018 11:39 pm

I'm building my first reverse flow smoker out of a 250 gallon propane tank. My fire box will be 30x30x30. How big should the opening on fire box and tank be? How big should the air intake be?
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Re: Firebox to cooking chamber opening

Postby k.a.m. » Fri Sep 14, 2018 11:34 am

SmohhkyD wrote:I'm building my first reverse flow smoker out of a 250 gallon propane tank. My fire box will be 30x30x30. How big should the opening on fire box and tank be? How big should the air intake be?

You will need a half moon 24" wide x 12" tall or 29" wide x 11" tall.
Your firebox comes in at 140% you could reduce that down to 112% and decrease your firebox size to 30" wide x 24" tall x 30" long.
That would also decrease your firebox to cook chamber opening to a half moon 21" wide x 11.5" tall.
Link to BBQ Pit Calculator
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Re: Firebox to cooking chamber opening

Postby SmohhkyD » Mon Sep 17, 2018 12:28 pm

Thank you
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Re: Firebox to cooking chamber opening

Postby Cesar50 » Thu Oct 11, 2018 1:19 am

k.a.m. wrote:
SmohhkyD wrote:I'm building my first reverse flow smoker out of a 250 gallon propane tank. My fire box will be 30x30x30. How big should the opening on fire box and tank be? How big should the air intake be?

You will need a half moon 24" wide x 12" tall or 29" wide x 11" tall.
Your firebox comes in at 140% you could reduce that down to 112% and decrease your firebox size to 30" wide x 24" tall x 30" long.
That would also decrease your firebox to cook chamber opening to a half moon 21" wide x 11.5" tall.
Link to BBQ Pit Calculator


Quick question what would happen if your opening is larger than the recommended of 21 wide 11.5 tall. Does that just mean it will be generating more heat but its still able to be controlled?

Im in the same situation my FB is 30x24x30 but the opening was left almost to 28 wide and 8-9 tall. I guess i need to calculate it haha

Thank you

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