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View Full Version : Anyone know Franklin's firebox design?


bjordmia
03-22-2015, 07:01 PM
I know he uses two tanks to make an insulated firebox with a 3" air gap. My question is this. Does he use a 36" with a 30" inside or a 30" tank with a 24" inside? I'm leaning towards a 30" with a 24" inside. Anyone know?

bjordmia
03-23-2015, 09:49 AM
Anyone? Don't be afraid to guess? I'm going off the pics above and in the 2nd pic, you can see the weld lines of the inner tank that circles the door. I'm really leaning towards a 30" outter shell with a 24" pipe slid inside. Anyone care to take a guess?

JS-TX
03-23-2015, 10:28 AM
Sorry but I don't see any of that, maybe somebody else can see that. This would be the 1st I heard of him using insulated fireboxes

Rusty Kettle
03-23-2015, 10:37 AM
My guess is I haven't got a clue... Sorry. You could always call and ask what is the worst that happens? He doesn't respond to you.

AlwaysSmokey
03-23-2015, 10:42 AM
Just a guess,.. but with the 2nd pick I'd agree with the 30 / 24 guestament.

FC BBQ
03-23-2015, 11:20 AM
I don't think the diameter of the fire box is 36". Also, to me, the face of the fire box is not thick enough to be insulated.

bjordmia
03-23-2015, 11:32 AM
Sorry but I don't see any of that, maybe somebody else can see that. This would be the 1st I heard of him using insulated fireboxes

I know for a fact that he has a 3" air gap between the 2 shells that make up his fireboxes. In this video, he mentions the 3" air gap at 0:48 seconds. Aaron Franklin's Pits - YouTube

In addition, you can see the burn marks on all of his firebox doors where the inner tank was welded to the front door panel. My question now is, are they 30" tanks with a 24" inside?

Nugetsius
03-23-2015, 11:44 AM
As a frame of reference, a 500 gallon propane tank has a 37" diameter and a 1000 gallon propane tank has a 41" diameter. So I would guess as you have 30" outer and 24" inner.

peeps
03-23-2015, 11:51 AM
Put a piece of paper up to the screen aligned with the vertical centerline and mark the bottom edge, top edge, and the top and bottom "weld lines".

Measure the distance from bottom edge to bottom "weld line" on your paper.

Using the 3" gap he indicated in the video, you can figure out the scale and estimate the diameters.

Just roughly eyeballing it, it looks like 30" and 24"..

bjordmia
03-23-2015, 11:55 AM
Put a piece of paper up to the screen aligned with the vertical centerline and mark the bottom edge, top edge, and the top and bottom "weld lines".

Measure the distance from bottom edge to bottom "weld line" on your paper.

Using the 3" gap he indicated in the video, you can figure out the scale and estimate the diameters.

Just roughly eyeballing it, it looks like 30" and 24"..

I love when people make me feel like an idiot, haha. Thanks for the help!!!

JS-TX
03-23-2015, 11:56 AM
thanks for the video! if you look at Jambos, the firebox is huge compared to the smoker chamber, I guess it allows the fire to breathe.

peeps
03-23-2015, 12:02 PM
I love when people make me feel like an idiot, haha. Thanks for the help!!!No worries...I often overlook the obvious. Sometimes you get fixated on something and can't force yourself to re-think the approach.

bjordmia
03-23-2015, 12:02 PM
thanks for the video! if you look at Jambos, the firebox is huge compared to the smoker chamber, I guess it allows the fire to breathe.

The firebox on Franklin's pits are relatively small compared to the volume of the cooking chamber. There's no Feldon's BBQ calculator going on there. They use max air flow with 10" exhausts and no vents on their fireboxes. All temps are controlled by opening/closing the door of the firebox. The increased air flow creates a convection oven type environment and I would guess adds greatly to the formation of the heavy bark. Just starting my first 500 gallon build and looking to test the design...

oldbill
03-23-2015, 12:11 PM
Put a piece of paper up to the screen aligned with the vertical centerline and mark the bottom edge, top edge, and the top and bottom "weld lines".

Measure the distance from bottom edge to bottom "weld line" on your paper.

Using the 3" gap he indicated in the video, you can figure out the scale and estimate the diameters.

Just roughly eyeballing it, it looks like 30" and 24"..

I love when people make me feel like an idiot, haha. Thanks for the help!!!Yep, Peeps managed to graduate from the University of Texas with an education, (even with the distraction of all those "2 legged DEARS" running around campus)! LOL!:wink:
BTW my vote is also for the 30" and 24".:-D

Rusty Kettle
03-23-2015, 12:13 PM
Put a piece of paper up to the screen aligned with the vertical centerline and mark the bottom edge, top edge, and the top and bottom "weld lines".

Measure the distance from bottom edge to bottom "weld line" on your paper.

Using the 3" gap he indicated in the video, you can figure out the scale and estimate the diameters.

Just roughly eyeballing it, it looks like 30" and 24"..

That is pure genius. I got to say I am impressed I never would have thought to do that.

peeps
03-23-2015, 12:38 PM
That is pure genius. I got to say I am impressed I never would have thought to do that.I have to do this often to get a quick guestimate of sizing.

CraigC
03-23-2015, 12:47 PM
Isn't this the guy who acquired these cookers from the man he used to work for got into some financial trouble?

bjordmia
03-23-2015, 02:33 PM
Isn't this the guy who acquired these cookers from the man he used to work for got into some financial trouble?

Yes, Franklin's first pit used to belong to John Mueller but has now been sold. Franklin has 5 - 1,000 gallon propane tank cookers that are now used. Google their names and you can find all you want to know about how it all went down. You'll probably even find several versions...

1MoreFord
03-23-2015, 07:27 PM
The 3" air gap insulation is a great idea. On the other hand his door design is terrible.It needs to open down to the bottom of the fire chamber to make it easier to clean out.

bjordmia
03-23-2015, 10:41 PM
The 3" air gap insulation is a great idea. On the other hand his door design is terrible.It needs to open down to the bottom of the fire chamber to make it easier to clean out.

I was thinking that as well. However, their style of cooking is a large fire with a very large coal bed and since there is no grate under the logs, I wonder if the lip is to keep the coals from spilling out. Not sure but he builds or has built his own pits and can't imagine him doing it too all 5 of his pits without a good reason.

pjtexas1
03-23-2015, 11:26 PM
Peeps knows his stuff. Not the first time he has had the solution to make us look average. :thumb:

Exhibit A:
http://www.bbq-brethren.com/forum/showthread.php?t=193800&highlight=apparently