Firebox to Cook chamber opening

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backyardbubba
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Firebox to Cook chamber opening

Post by backyardbubba » February 5th, 2019, 9:45 am

Hi all. I am literally brand new to this site (15 minutes) and I want to thank everyone in advance for all the great info I/we have gleaned already from this site. My neighbor (an experienced welder) and I are designing a pit and want to get it right the first time if at all possible for all the obvious reasons. We are hyper-focused right now on the opening between the firebox and cook chamber and we have a question.

What are the real-world consequences of either too large or too small of an opening??? We are learning ... so thanks in advance for tolerating such a basic question as sometimes we need to gut check what we think we know with those that actually do know something!

Look forward to hearing from someone ... Thanks again.

BYB



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ajfoxy
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Re: Firebox to Cook chamber opening

Post by ajfoxy » February 5th, 2019, 4:40 pm

Welcome aboard.
One of the more knowledgable fellers will be along shortly to answer your query.


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Big T
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Re: Firebox to Cook chamber opening

Post by Big T » February 5th, 2019, 6:54 pm

Welcome! If the opening(throat) is too small it causes a choke point and you can't draft the hot air from the fire box(FB) into the cook chamber(CC) if it's too large you can't control the rate that it drafts from the FB so it's a pretty critical part of the build that can cause some real pains when you're trying to control your temperatures. There's a calculator page on top of the forum that has a pit calculator as well as several other calculators that can get you all of your dimensions. Don't be afraid to ask questions and one of the guys will try to help you out.


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Dirtytires
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Re: Firebox to Cook chamber opening

Post by Dirtytires » February 6th, 2019, 1:53 am

You will constantly be fighting your temp if you get it wrong. Too small and the cook chamber will never heat up and too large will mean that you cannot possibly get a small enough fire. I purchased plans on the site and mostly followed them. I did add a damper for extra controll just in case but don’t use it much as my opening is spot on. Follow the calculator on the site and you will end up with a well working, easy to control pit.



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Pete Mazz
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Re: Firebox to Cook chamber opening

Post by Pete Mazz » February 6th, 2019, 5:28 am

Welcome


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