Offset build...

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babydoc

Smoke Blower
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So....technical question here. How much insulation for a fire box is good/adequate/overkill? I've seen some guys have about half an inch or less between the outer and inner boxes, but I was thinking more like 2 inches with water heater insulation in the gap.

Too much?

Also, was planning on making her a reverse flow.... any pro's and con's thoughts on that are appreciated. From what I know temp regulation is easier with the RF...with the trade off that the CC is really the same temp throughout...correct? So it might be tricky to smoke more than one type of protein that may require different temps, right?
 

golfpro2301

Smoking Fanatic
Jun 6, 2012
534
143
Jacksonville, FL
Insulation will depend on few things. Where do you live and what is FB metal thickness. Warmer weather and thicker metal less insulation you will need. I have 3/8” FB and 2” insulation. I should have gone 1” as I meed heat to escape more as so much gets trapped in thicker metal

As far as RF and even temps I would go modern offset. Get heat moving vertically asap right put of FB and let it go across top cooking down. You will get even temps this way and much better airflow
 

babydoc

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Insulation will depend on few things. Where do you live and what is FB metal thickness. Warmer weather and thicker metal less insulation you will need. I have 3/8” FB and 2” insulation. I should have gone 1” as I meed heat to escape more as so much gets trapped in thicker metal

As far as RF and even temps I would go modern offset. Get heat moving vertically asap right put of FB and let it go across top cooking down. You will get even temps this way and much better airflow
Gotcha, so the inner portion is 1/4" pipe and the outer box will be 3/8"....all because that's what I have.

Modern offset meaning traditional? Not RF?
 

babydoc

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For FB you are saying 1/4” inner then insulation and 3/8” on outside???

Yes traditional offset
Wanted a rounded top for the firebox itself...thats why I went with the pipe. Have a sheet of 3/8 already so gonna use that for the outer box. I know the opposite would be ideal...
 

golfpro2301

Smoking Fanatic
Jun 6, 2012
534
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Jacksonville, FL
That is way overkill and extremely heavy. Build square box out of 3/8” with no insulation and use 1/4” for collector on stack side. 1/4” CC and that pit will last lifetime
 

babydoc

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LOL....I was waiting for the heavy comment. I just cant justify buying more sheet when I have some already and its stupid expensive now.

So insulation is overkill? Plain and simple? No advantage to a curved/tube ceiling verses flat box ceiling?
 

golfpro2301

Smoking Fanatic
Jun 6, 2012
534
143
Jacksonville, FL
There is benefit of curved inside but you are using $1k worth of steel for a $1 job on outside. If want to use curved put sheet of 3/8” up for sale for $800-$1k or trade for sheet 1/4” and 1/8”. DONT use that 3/8” for outer shell.

Use 1” insulation for pipe inner. Will be 1” in 4 places but a lot more in corners and will be fine. 1/8” on outside will hold it all in just fine. If dont want to insulate door find piece of 3/8” or 1/“2 for that
 

3montes

Master of the Pit
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Dec 26, 2007
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Beautifull shores of Lake Superior
I have a conventional flow offset with tuning plates. I’ll never go to any other platform it’s very versatile. Firebox and chamber are 3/8” no insulation. The real enemy is not cold it’s wind and rain. I’m in Minnesota and have smoked outside at just above zero temps. On a calm day it’s no problem. I just start with a bigger fire at the outset. Once the steel is all up to temp it takes no more wood than in the summer.

In terms of a firebox I strongly recommend a top loading door and a front door for ash removal. My firebox is more of a square shape with sliding vents on three sides. Another design I highly recommend. It’s so much easier and pleasant tending your fire from a standing position through the top door than stooped over or kneeling on the ground through the front. Also I can open the top door and drop a grate on the opening for live flame searing. With the intake vents on three sides of the firebox you never have to crack the front door for proper air flow. I’ve always felt if you are having to use your door as a vent it’s designed wrong. Good luck and keep us posted.
 
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babydoc

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I have a conventional flow offset with tuning plates. I’ll never go to any other platform it’s very versatile. Firebox and chamber are 3/8” no insulation. The real enemy is not cold it’s wind and rain. I’m in Minnesota and have smoked outside at just above zero temps. On a calm day it’s no problem. I just start with a bigger fire at the outset. Once the steel is all up to temp it takes no more wood than in the summer.

In terms of a firebox I strongly recommend a top loading door and a front door for ash removal. My firebox is more of a square shape with sliding vents on three sides. Another design I highly recommend. It’s so much easier and pleasant tending your fire from a standing position through the top door than stooped over or kneeling on the ground through the front. Also I can open the top door and drop a grate on the opening for live flame searing. With the intake vents on three sides of the firebox you never have to crack the front door for proper air flow. I’ve always felt if you are having to use your door as a vent it’s designed wrong. Good luck and keep us posted.
I was just looking at another smoker with exactly the same...3 side vent option. I think I'm gonna go with that.

Again I've never used an offset so I'm a bit ignorant with both the build and use. A conventional flow system requires a little more tending...correct?

Wind complicates things due to cooling? Or flaming up the fire box?
 

3montes

Master of the Pit
OTBS Member
Dec 26, 2007
1,274
119
Beautifull shores of Lake Superior
I’ve never used a reverse flow so I can’t say it it requires anymore or less tending than a conventional flow. I feel it’s a misconception on how much tending a wood smoker really takes. Once up and running I can mow lawn and come back forty five minutes later stir the coals and throw another small split on to keep the coal bed going.

My advice to anyone wanting to get into stick burning is first get rid of the electronics. Stop hand wringing over small temp swings and why do you need to know when a brisket or pork butt is at 120 degrees. Learn your smoker get to know how to manage a fire. Do some tests using oven therms at first which is what I did to gauge what your internal pit temp is compared to what your outside therms are telling you. I know when my door therms are reading about 215 I’m at 250 to 260 internal. That’s all you really need to know.

There will be a learning curve but that curve gets smaller when you stop worrying over every single degree of temperature and don’t over react to a temp swing of 50 degrees.

My experience is a cold wind is the biggest enemy next to rain or snow. A 15 degree above zero on a calm day poses no problem for me. Ymmv.
 
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babydoc

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Awesome! Great advice!! I'm sure there will be a learning curve...thats part of the fun right?
 

3montes

Master of the Pit
OTBS Member
Dec 26, 2007
1,274
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Beautifull shores of Lake Superior
I find it easier to use small to medium splits of wood. Much easier to increase temps with another small split than it is to try to tame to big of a fire and a hot pit.

I prefer cabinet doors over one large door that swings up with a counter weight. When you watch someone open that large mass of a door it creates kind of a vacuum and pulls all the smoke and heat with it. That’s where the if you’re looking you ain’t cooking phrase came from I believe. Another axiom I don’t subscribe to. If I open my cabinet doors slowly I lose hardly any smoke and little temp drop. I like to spritz so I’m opening my doors fairly regularly. Feel free to ask any specific questions you may have and I or some other stick burners will try to answer.
 

babydoc

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Aug 13, 2022
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I find it easier to use small to medium splits of wood. Much easier to increase temps with another small split than it is to try to tame to big of a fire and a hot pit.

I prefer cabinet doors over one large door that swings up with a counter weight. When you watch someone open that large mass of a door it creates kind of a vacuum and pulls all the smoke and heat with it. That’s where the if you’re looking you ain’t cooking phrase came from I believe. Another axiom I don’t subscribe to. If I open my cabinet doors slowly I lose hardly any smoke and little temp drop. I like to spritz so I’m opening my doors fairly regularly. Feel free to ask any specific questions you may have and I or some other stick burners will try to answer.
How important are all the calculations? Like Feldon's...and what not? To be honest its actually really helpful to have something concrete to start with. I just wonder how closely I need to adhere.
 

TH-n-PA

Meat Mopper
SMF Premier Member
May 28, 2022
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I have modified/expanded a wood stove but never built a smoker.

if you don't find what you are looking for you might get some input here.

 

oscar

Fire Starter
Dec 25, 2012
60
58
Central New York
Interesting comments all around. As for the top load fb, I did that on mine, and a removable grate, as mentioned. Thought I'd do a few burgers or dogs while smoking in the cc. Problem was, as soon as you flip that lid, you're long smoke is kaput. Other problem was, rain got in, and the inside of the fb started peeling and the charcoal box rotted away. Yes, it's handier to load, but has its drawbacks.
 

3montes

Master of the Pit
OTBS Member
Dec 26, 2007
1,274
119
Beautifull shores of Lake Superior
Hmm I guess I haven’t run into that issue. If I have long smoke stuff on like brisket or butts I dont grill things on the fire box. I will throw other things in the smoker along side the long smoke stuff like wings or chops for lunch or dinner. I use it for reverse sear stuff like steak or tri tips where they smoke for a bit and then hit the fire box grate for the finish.
 

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