SFB opening size for Char-Griller Duo

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Original poster
Feb 8, 2011
Hi. Long time lurker first time poster.

I talked my neighbor into buying the Char-Griller fire box to attach to his CG Duo. I have read the mods for the smokin-pro and duo which usually include some type of baffle. I am contemplating cutting the hole smaller than the knock-out to eliminate the need for a baffle and turning the charcoal pan up-side-down for dispersion. The cooking chamber on the Duo is much smaller than the smokin-pro but has the same size knock-out. I am thinking that would be way too much heat.

The fire box has a round damper on the end that would attach to the chamber for using the fire box alone as a table top grill. At a minimum I was thinking of leaving this damper open and cutting an equivalent round hole in the cooking chamber. This seems like it would not allow for enough flow. The next step up would be to cut out the entire round damper with equivalent round hole in the cooking chamber. I am thinking that this would be a good starting point but still concerned that it would not allow for enough heat or flow.

The next step up would be to leave both knock-outs in place and cut smaller, say half the area, out of both football shapes.

Does anyone have any insight into the best size opening? Any optimum positioning of opening as in low on chamber if not using the whole knock-out?
I recommend using the entire knockout, otherwise I believe you will have trouble getting up to proper cooking temps. Turning the cook chamber charcoal grate upside down will act as a baffle.
If it were me i would knock the whole football out and then use either the charcoal pan oe build some other baffle. When i did mine i was worried about getting enough air flow and heat into the chamber.So i took the whole football out and did some smokes first to see how the airflow and heat and smoke worked before i did anything.Now i build a small heat baffle,then i lined the bottom of the chamber with fire brick and made a spot for a small waterpan to sit down on the brick on the firebox end.This works well for me,that way i can still get my heat up if i do a chicken or turkey.I suppose you can first cut smaller knock outs,then do a few smokes and see how it does.you can then always go back and take the rest out if ya need to.Its easier to cut more out than to take too much out in the first place! Give it a try and see what happens,just be sure to let us know what ya think!
Welcome to SMF. There are a lot of very friendly & knowledgeable folks here to help you. I urge you to sign up for the free E-course. It will give you the basics, & even if you are an experienced smoker you may learn something new. Then start asking questions. Good luck & glad to have you aboard. Don't forget we all love Qview! Now if you would go to the roll call section & introduce yourself, so we can give you a proper welcome.
Calumet-you need to remove the knockout so there is adequate flow between the sfb and the cook chamber.  The sfb looks oversized for the size of the cook chamber-just remember that you don't have to build a big fire to fill the firebox-smaller fires work just as well. It all about fire control and using the air intakes to control your temps.
Thanks to everyone for your input. Yes, the firebox opening does look too large for the cook chamber on the Duo. It appears nearly half the size of the Smokin pro. I like the idea of taking out the entire knock-out and then building smaller fires.

When I turned the charcoal pun upside down, there is a small gap (about 1/8") when pushed up against the SFB wall due to the ends of the grate extending slightly past the pan. I think I will grind those off or should that gap remain.

Thanks again.
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