Firebox questions

[Kcd2016]

If you look around the 6:10 mark heres a pretty good shot of the inside of the firebox

https://youtu.be/2jA_an9e7IA

[dacolson]

4:20 ish on this on shows the outside of the stack pretty clearly but does not show the inside.
https://youtu.be/2jA_an9e7IA

[Big T]

This is the thread that I think back to when guys try to build a jambo clone. https://smokerbuilder.com/forums/viewto ... ambo+clone There's some good information in there from Tom about how everything needs to be to avoid some common mistakes by us backyard builders. I think having intakes on the FB where a jambo has a fixed intake kind of helps avoid those downfalls but if the throat and stack exit are misaligned it can still have some issues.

[Kcd2016]

I just stumbled onto outlaw bbq smokers. It looks like they've copied the jambo design. Here's a look at their fb throat/baffle. They also don't have the throat at the top of the fb.

[Pete Mazz]

It was fun running Lou Ann! According to Frank, the heat/smoke swirled up and down thru the CC. Like most smokers, if designed right they just work.



As you can see from this experiment, the smoke does not go right out of the stack but circulates around the entire CC.

[dacolson]

Wow! that is surprising! Great experiment. Wonder what the temps were and if higher heat = more velocity. Would that push it out the stack faster. Man. Now I want to put a camera in the pit!

[Pete Mazz]

No heat, just a smoke bomb. The draw was created with a variable speed PC fan on the stack.

[D . Jur]

Whats about that kind of baffle? Is it work ?

That design seems counter productive to me. Heat naturally rises so putting a baffle that angles down would make it a little more difficult for the heat to leave the FB. Also once the heat clears the baffle it will rise so it looks like you would just move the hot spot down a few inches. I feel that a baffle similar to Dave's or tuning plates are the 2 best options for an offset smoker but I could be wrong and it wouldn't be the first time.

I don't have a firebox exit damper yet, but I want to make one.
This particular picture is from the Mobergsmokers video.

[D . Jur]

I have a square firebox with a flat bottom, and octagonal CC.
I think to experiment with dampers, as in the Jumbo topic.

[dacolson]

What are you showing here? I don’t see a damper. Just a rectangular throat.

[D . Jur]

There are several questions for experienced builders ...
1. Is the distance from the bottom of the firebox to the throat in my photo normal, or should it be shorter?
2. How important is the shape of the bottom of the firebox, round or flat?

[D . Jur]

What are you showing here? I don’t see a damper. Just a rectangular throat.

I am from Russia and write and think in English a little slowly ...
I wrote the questions.
There is no damper yet, because I am thinking which one to do.

[Dirtytires]

Your distance is acceptable. Definitely would not go shorter but a longer distance would help to block some of the direct heat and possible smooth out your hot spot in the cook chamber.

I am a big fan of a flat bottom on my fire boxes. It allows me to use a slide-out ash pan so that cleanup is much easier. I feel the square firebox just gives me more room for loading and the log rack. Round is fine tho. As long as it is properly sized, the fire doesn't really care and cooking will be he same with either.

[dacolson]

What are you showing here? I don’t see a damper. Just a rectangular throat.

I am from Russia and write and think in English a little slowly ...
I wrote the questions.
There is no damper yet, because I am thinking which one to do.

All good D. Jur. I misunderstood the question sir. Throat location is good. And I agree that flat or round bottom both work well. I have mainly built square fire boxes.


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[D . Jur]

Your distance is acceptable. Definitely would not go shorter but a longer distance would help to block some of the direct heat and possible smooth out your hot spot in the cook chamber.

I am a big fan of a flat bottom on my fire boxes. It allows me to use a slide-out ash pan so that cleanup is much easier. I feel the square firebox just gives me more room for loading and the log rack. Round is fine tho. As long as it is properly sized, the fire doesn't really care and cooking will be he same with either.

May I ask for a photo of your firebox from the inside?

[Dirtytires]

A picture of the inside of my firebox will not show up....it's just black soot in a dark box! What are you looking for specifically and maybe I can describe it or find a way to take a picture.

[dacolson]

This is the only pic I have of my standard offset with a square FB. I sold it so I can’t get more unfortunately. I’m attaching a pic of the baffle as it was when I sold it. When I saw him last we added a 6” extension of the baffle to extend it up above the grate.








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[D . Jur]

This is the only pic I have of my standard offset with a square FB. I sold it so I can’t get more unfortunately. I’m attaching a pic of the baffle as it was when I sold it. When I saw him last we added a 6” extension of the baffle to extend it up above the grate.








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This is what I need, thanks. I will try to work with a similar charcoal basket.

[D . Jur]

It looks like there are two types of pitmasters ... some work with similar baskets, others form a coal bed right on the bottom of the firebox ...

[dacolson]

From what I can see, it's more common to use a fire basket in a square firebox so you can get the coals off the bottom and get air underneath. In a round firebox, you have a natural space under the coals. Either way, I like to have the wood up a little above my vents so air travels under the coals. It helps to keep them burning clean.

[Big T]

[D . Jur]

One more question ... I made a mistake in the calculations and the firebox is now less than necessary? What does this affect?

[dacolson]

You may have trouble getting your pit hot enough. How much too small are you talking about?

[D . Jur]

You may have trouble getting your pit hot enough. How much too small are you talking about?

47%

[D . Jur]

But I did not take into account this volume in the calculations, which is to the left of the dotted line, although this does not change much ...

I will change this ... cut and grow to the desired size.