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Smoker Build - How Big Firebox for 120 Gallon Smoker??

Posted: Fri May 29, 2020 1:14 pm
by MCPMartin
Quick question - I'm building a 120 gallon smoker, and I'd like to know "the rule of thumb" (if one exists) for how big a firebox should be per the size of the smoker. I've read some guys use 20% and others say they just eye-ball it.

Re: Smoker Build - How Big Firebox for 120 Gallon Smoker??

Posted: Fri May 29, 2020 1:50 pm
by k.a.m.
Welcome to the forum.
Here ya go I ran your numbers this is how I would proceed click on the link:
Link to BBQ Pit Calculator
On the exhaust go 24" instead of the recommended 20.55"
On the intakes if you go vertical horizontal slides go with three 6" tall x 2" wide.
On the firebox to cook chamber opening a half moon of 16" wide x 8" tall will work.

Re: Smoker Build - How Big Firebox for 120 Gallon Smoker??

Posted: Wed Jun 03, 2020 12:17 pm
by MCPMartin
k.a.m. wrote:Welcome to the forum.
Here ya go I ran your numbers this is how I would proceed click on the link:
Link to BBQ Pit Calculator
On the exhaust go 24" instead of the recommended 20.55"
On the intakes if you go vertical horizontal slides go with three 6" tall x 2" wide.
On the firebox to cook chamber opening a half moon of 16" wide x 8" tall will work.


Thank you for the awesome link & information! There's a lot of great information there, and I appreciate it.

Re: Smoker Build - How Big Firebox for 120 Gallon Smoker??

Posted: Wed Jun 03, 2020 2:06 pm
by k.a.m.
MCPMartin wrote:
k.a.m. wrote:Welcome to the forum.
Here ya go I ran your numbers this is how I would proceed click on the link:
Link to BBQ Pit Calculator
On the exhaust go 24" instead of the recommended 20.55"
On the intakes if you go vertical horizontal slides go with three 6" tall x 2" wide.
On the firebox to cook chamber opening a half moon of 16" wide x 8" tall will work.


Thank you for the awesome link & information! There's a lot of great information there, and I appreciate it.

Glad to help.