Can't get smoker up to temp. Design problem?

[blairb]

I recently purchased this smoker. I have tried on 2 occasions to get it up to temp and hold with little success. I have tried all combinations of dampering (even nearly closing off smoke stack), built a really hot fire for several hours (glowing red fire box), and the hottest I have been able to get is about 210. The weather was mid 40's with little to no wind. I have been pondering some modifications and would love to hear any input from the community.

• I am not using this for competition, so propane assist is one avenue I am looking at. I don't mind keeping a fire in the fire box for smoke and using the propane to keep it up to temp. Judging from my experience so far with this smoker the propane burners would probably need to be in the cooking chamber not the fire box.
• I am considering possibly converting it to a reverse flow smoker.
• Does the firebox need to be connected closer to the smoker?

When I make a mod, I would like to do it right the first time and fix it.

The dimensions are as follows:

Fire box: 28"x28"x28"

Square tube that runs from fire box through smoker to stack: 4"x8"

Square tube has total of 12 vents inside the smoker that are 1 1/2" diameter

Distance from fire box to smoker is 5 1/2"

Cooking chamber: 72"long x 44"wide x 32"high

There is 2" of space under the square tube

There is 7" of space above the square tube to the bottom of the cooking surface 

2013-01-22 10.51.50.jpg

• blairb
• Jan 22, 2013

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• blairb
• Jan 22, 2013

2013-01-22 10.54.03.jpg

• blairb
• Jan 22, 2013

 

[fagesbp]

I think the opening from FB to CC is stopping the heat from moving into the CC and also the distance between them is allowing a little room to cool.

 

[beef77]

Maybe baffles and a stoker fan

 

[fwismoker]

4 suggestions i can think of trying.

1) increase size of pipe from FB to Smoker

2) Heat wants to go up so if you resize the pipe then give it more of an "up draft"

3) use lump charcoal

4) insulate the firebox 

The  FB looks penty big. 

 

[fwismoker]

I think the opening from FB to CC is stopping the heat from moving into the CC and also the distance between them is allowing a little room to cool.

My offset smoker(click on my avatar) has about a 3 foot pipe and i have no problem transferring the heat, i just have it insulated. 

 

[daveomak]

Blair, morning.....   A few things I noticed..... You are on your way to a great smoker with a few mods... 

Below are the numbers I used to calculate certain dimensions....

http://feldoncentral.com/bbqcalcula...85&fi=15,4,0,65.86,1.10&fc=14.96,21.15,175.62

Firebox to cook chamber opening needs to be.... 175 Sq In..  ( 20? x 9? ) and make as low as practical in the CC...  

I would remove the pipe totally.... then bolt or weld the firebox to the cook chamber....   Match the openings of the FB and CC when bolting... Use some Wood Stove gasket between the 2 pieces for an air tight seal...

The smoke stack is supposed to be ( 50 sq in )  7 x 7 and 22" above the top of the CC...  or 8" pipe same height.... if the existing stack is somewhat close, go with it...  The exhaust stack should enter the CC just above the lowest grate...  if possible...  

After all that is done, you will find "tuning plates are necessary....  unless you build a reverse flow.... 

I also recommend a second intake to the firebox above the fire grate to adjust the heat flow through the smoker.. maybe 5"x 2" adjustable.. 

Also the FB needs a grate about 5" or so above the bottom of the FB....

Any questions ???   I'm here as are other members whom are experts in building and modifying smokers so they work as they should..... PM me any time...    Dave

 

[JckDanls 07]

So If I am reading your post right... you say the square tube is connected from firebox to the exhaust stack ? So It's all one piece all the way through the cook chamber ? IF that's the case I would say that is most of the problem right there... As Dave said I would remove the tube completely and make openings bigger and go with a reverse flow.... Dave will stir you right with all the right sizes for openings and stack height...

 

[show me smoke]

Yes that is a big fire box seems to be a 1/4 size of the cooking chamber...the pipe connecting the two is way small...I agree make it larger..or cut it out and slam the firebox to the cooking chamber.