where do I start

[thatlevi]

Before I found this site I thought I was doing pretty good building my smoker, but after reading a bunch of post here I am Broken and thinking I need to start over. So help please!! how big of a fire box do I actually need is there some sort of formula. does an insulated chamber mean I need can have a smaller fire box. warming box I assume affects the fire box size. How thick does my reverse flow plate need to be does that matter? I am thinking about insulating cause my tank is pretty thin. Please help point me in the right directions I started this project 2 and a half years ago. when I have time. I want to do It right

Thanks Travis

I could go on for pages but I think I will stop there

[Frank_Cox]

I should be able to get on the site later bud, I'm replying from my phone right now... Workin on a plasma table with a buddy of mine. I'll be on later

Sent from my iPhone using Forum Runner

[Tom_Heath]

Travis, can you post up a pic or two of what you have so far.

That will help alot.

But to answer some of your questions,

Yes with an insulated cook chamber you could in theory have a smaller firebox.
The ideal situation would be to have the whole thing insulated. Firebox and all, warmer too.
Thats the perfect world with no budget.

But there are tons of smokers out there that are not insulated at all, they just need more attention to maintain temps.

For the RF plate,
Since you have a thin wall tank, the thicker the plate the better the heat retention will be. Meaning you will maintain and also hold temps better.

Next question for ya is how cold does it get for ya in the winter and how much do you plan to smoke in the winter.
I think you may have posted where you are from but I'm the slow kid here and can't remember.

If you need help with loading the pics, send me a PM and I'll get you a link to help ya out.

[thatlevi]

Minnesota is cold. smoking in the winter is not on my mind I have always been thinking insulation. Cause I go big so far the most I have in my smoker is alot of time my fire box and tank were free I got 150 lbs. of good welding rods for 8 dollars at an auction so I don't have alot of money in it. I will try to post pics tomorrow. Had straw to bale tonight (just helpin a friend) thanks

[MattS]

The key to this is giving us the dimensions of your smoker and we can work off that.
The RF plate can be as thick as you want it. The thicker the better for heat retention especially on thin walled smokers.
The size of the fire box really only matters on the small size. It can be as big as you want it, but it needs to be big enough to supply your smoker with enough heat. There are formulas to determine you firebox size compared to your cooking chamber.

[thatlevi]

so the cooking area is 32 x 32 x 60 that would be after the RF plate is welded in the current fire box is 16 x 24 x24 that is 1/8 inch thick I was planning on a 6 inch stack. I was think warming box don't know the size yet

[Tom_Heath]

The dimensions we are looking for are the outside numbers or gallons. The numbers are best.

If its like the 300 gal tank I have it should be close to 32 ish by 60" long.

By my guessing at the numbers, I would say that you are a little small on the firebox and just a tad small on the stack size at the rated length of 24 inchs.

I will check the other calc when you verify the numbers. Since you can increase the stack height to help make up the cu inch's.

Like I said you are close now, just a little fine tuning once we get the numbers. Its amazing the difference it makes when you compare to like rigs, when one has a slightly larger cu inch on one of the openings.

I may suggest that you look at Franks idea of the adjustable baffle plate.

Another question would be,
Are you planning to run any type of stoker or guru to maintain temps? Or PID control?

[thatlevi]

the dem. would be 32depth 60 length 45 heigth outside dem. I don't know what a PID guru or stoker is in smoker terms

[Tom_Heath]

The guru and stokers are thermostat controlled fans that turn on and off depending where the temps are. Most of the time they mount to the air intake on your firebox.

A PID control is an electronic devise that can be used to cycle a fan, a pellet drive, a pellet dump or even a damper. Just about anything that moves can be cycled with a PID.

I'm thinking that you may have the same tank that Matt used on his build.

When I get home I will check the numbers again.
Sent from my PC36100 using Tapatalk

[MattS]

Is this an oval tank? Its sounding like your firebox is on the small size.

[thatlevi]

It is an oval tank. it has been mod. so it is wider than normal it was 265 gallons before mod prolly 300 after mod
I have considered some sort of electronically controlled device for temp.

[MattS]

For that tank you will need a firebox of around 26,000+ cubic inches. The one you have now is 9,200 cubic inches.
Height X Width X Length (all inches) will give you the cubic inches.

You smoker is around 79,000 cubic inches for reference.

[thatlevi]

so where do I go from here suggestions on what I should do. bigger fire box two fire boxes ?

[MattS]

Personally I would just deal with the firebox. Build a bigger firebox with a good RF plate. That will make a huge difference on your smoker.

A warmer box doesn't really determine the size the firebox in my opinion. Its the other way around. A warmer box is essentially just that, a warmer box. The heat radiating off the firebox will do well with working the warmer box. Or you can build a adjustable vent like Frank did on one of his builds going from the firebox into the warmer box if you want to be able to add more heat and some smoke.

As far as insulating, it does help, but not a necessity. With a good firebox, thick RF plate and a well sealed smoker, you will be in good shape. The biggest enemy on any smoker is too many air gaps.

[Tom_Heath]

Which calc are you using Matt?

When I run the numbers even for a square cook chamber I come up with 28800 cu in.
And 13824 cu in for a square FB of 24x24x24.

If he went 30x24x24 that would I think yield a cu in of 17280

I am using the exel calc, and I am curious why some of the numbers are coming up different.

But I would have to agree,
With a heavy RF plate and slightly larger air intakes, it would run fine.

Especially if it was gonna be run by a nice stoker set-up.

Any chance you can post us a pic travis?

[thatlevi]

Sorry it was my wifes b-day today so I could not seek away maybe tomorrow

[Tom_Heath]

No problem Travis, I think most of us have been there done that.

A guy has to know just how far to push it.

And no I don't have an X from pushing it to far. LOL She did the pushing, one time to many.
Therefore I upgraded to a model with more options. And less mileage.

[Frank_Cox]

No problem Travis, I think most of us have been there done that.

A guy has to know just how far to push it.

And no I don't have an X from pushing it to far. LOL She did the pushing, one time to many.
Therefore I upgraded to a model with more options. And less mileage.

[Frank_Cox]

so where do I go from here suggestions on what I should do. bigger fire box two fire boxes ?

Hi Travis,
I have not been able to get to the compy lately as I have been working real late the last few days, I will also run the numbers but it sounds like Tom and Matt are steering ya right. You can always go bigger on the firebox and it won't hurt anything. You can also have more air inlets than you need and be ok. As long as the cook chamber to firebox opening, baffle plate gap, and stack are sized properly you will be fine. I always like to go a little bigger with the BP gap and make it adjustable. Works real nice for fine tuning your cooker.

[MattS]

Tom. I calculated his oval tank based off the 32 deep X 45 tall X 60 long. He said his firebox was 16 X 24 X 24.

I calculated his cook chamber as the oval shape. But I do think I calculated it as 48 tall, I don't remember. But I measured the volume of a 32 cylinder and then added the volume of the left over box. So I took (16 squared) 256 X 3.14 X 60 = 48691. Then the left over box measurement is 32 minus the total height. 32-45=13. So the left over box is 13 X 32 X 60 = 24960. So I got 24960 + 48691 = 73921 cubic inches

[Tom_Heath]

Right on man, I got it back on track now.

I had forgotten that when I enter a dimensions into the third field of the cook chamber that it shows a cu in thats 1/3 the actual amount.
If I enter gallons or if I enter the numbers for a tank it will show the total cu in.

Sucker had be going in circles.

I still want to see a shot of how the firebox is cut into the tank before I make a judgment if I think the slightly smaller firebox will do the trick.
Such as if its just butted up to the tank or connected with pipe, then it may be hard to make it work on the small side. If its cut into a helical end there it generates alot more radiant heat.

[thatlevi]

So here it is tell me what you think I need to do different or keep ( I can Take it)

[Tom_Heath]

OK,

Thats a big cooker. But I have personally ran a larger rig that actually had a smaller firebox.

If it was me, I would leave the upright smoke tunnel, but I would cut two large as possible butterfly dampers into the cook chamber side of the firebox.

What you have is a great idea, its nearly the same as a backwoods. The backwoods counts on the insulation in it to make it work nicely.
With that said, on a warm day you could close the butterfly damper and most likely run off just the smoke tunnel. But on a cool to cold day, I would say that you would have the butterfly open.

Next would be to use, not a RF plate but several tuning plates.Basically several pieces of maybe 1/2in plate that would be about 6 in by 30 ish inchs. They would sit on a lip that would run from end to end of the tank on both the front and back. You then slide the plates to make up different gaps allowing the heat to be even.

The other option would be to have a couple 4 or 6 in pipes that run from the firebox going left about 3/4 of the way to the end of the cook chamber.
Then have varied size slits cut out of the pipes to let the heat rise at different locations. This route does not use the tuning plates and is much tougher to get right on the money.

Personally I would not change the firebox since its already complete.

Insulating it is definitely an option, an inch to an inch and a half would be plenty. Koal wool is one of the many options. All it takes is to mount riser pins at key locations for the new outer skin to secure to. Using a light gauge sheet metal would make skinning it a breeze. The only problem I can see is that you would need to make or buy extended pin hinges so that the doors would pivot at the outter most edge.

And even more so I would leave the firebox the size it is, if I was using a stoker. Here is the link for the site that the stoker is on.
https://www.rocksbarbque.com/

You may notice on that page that they have jackets for the bullet style smokers.
That may be an option for ya on the insulation deal. Get some old army blankets (wool) and drap them or make little brackets for them to hang from. This method works nice so long as you can keep the blankets dry.

[Frank_Cox]

I think Tom is right on the money. I would go with the tuning plates myself for sure and if you insulate the rig you wont be sorry. it will save you a ton on fuel and effort keeping your temps where you want them. I like what you have so far and that will be a great rig to cook on with those huge doors

[thatlevi]

So if I stay with my RF plan I would need a bigger firebox or if I go with tuning plates I would be ok with the fire box I have?

Do tuning plates have to be adjusted every time or are they set after you get them where they need to be once.