how big of an opening for the firebox

[promise'cajunbiker]

Have never built a smoker before and going to make my first attempt. Going to use 20" pipe 5' long, opting for the reverse flow type. Was going to make the fire box sqaure(rectangle)18x24. I just dont know how large to make the firebox opening. I also think im going to use 4" pipe for the exhaust, think im on the right track, but could be wrong. You know how us newbies are

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[fatback joe]

I am not an expert builder by any means, so take this FWIW. I would make the opening as big as you can, no reason to restrict the flow from the fire box to the smoker......especially on a reverse flow. You will control the heat by the size of the fire in the box and dampers not the opening to the smoker.

Just my 2 cents.

 

[richtee]

Hey promise! Get over to the "Roll Call" forum and say howdee formally, along with your equipment list...or plans. A quickie: Input must equal output, with output equalling ALL of input...EG: leaks, etc.

 

[chris_harper]

for a smoker that big, you will need a bigger smoke stack. a 4" is about right for a 55-gallon drum, ie: my smoker. like joe said, there is no reason to skimp on the opening to the smoker from the firebox on a reverse flow design. your meat will not see any flames that enter the smoker, as they would be under the plate. hopefully coley will see this soon.

btw, welcome to SMF.

 

[cowgirl]

Mine is made from a 20" pipe...5' smoking chamber and 2' fire box.

The opening between the 2 is 6" BUT.......Mine is not a reverse flow.

Welcome to the forum anyway.

 

[promise'cajunbiker]

Fatback, I wasn't really planning on a damper between the firebox and the smoker. I was just planning to control by the intake of air. That's the way we do the one that we have here at work and it does well. Again, I'm just the new guy

 

[deejaydebi]

I don't know if it's a general rule or anything but It seems like most of the side fireboxes I've seem the opening is about 1/3 to 1/2 the size of the firebox. Just one of things I was asking about when I went to the BBQ fair a few weeks back.