250 Gal Propane Tank build questions

[FlightRN]

Hello all! I have been lurking and reading in prep for doing my own build and now I think it's time. I will mainly be using this to do big cooks for our church at community events. I have several questions:
1. I was thinking of making mine a reverse flow smoker. I do ribs quite frequently and they have become a favorite at our family campout. Would a reverse flow also be able to cook 100+ hamburgers and 100+hotdogs well (ie bring the temp up enough to sear)?
2. I am using a 200lb propane tank as the fire box. Can I connect it to the CC using three 6in steel pipes with adjustable baffles rather than cutting the "half moon"? Is this a dumb idea?
3. Was thinking of using short sections of 6in steel pipe with adjustable baffle as my air intakes on the fire box also, again is this a dumb idea?

Thanks in advance for your wisdom/experience/help!!!

[KMM]

I understand what you are trying for.....not sure it will give the results you envision. First, the surface area of the three 6" pipes will probably fall short of the half moon configuration. (Remember to use the inside diameter of the pipe, when calculating surface area). Second, the three pipe config could cause uneven temps in the cc. Granted, baffling individual pipes could, in theory, resolve uneven heat in the cc....but keep in mind, those same adjustment to the cc will have a definite (delayed) effect on the performance of the firebox. Between the air inlets on the fb, baffles between the fb and cc, tuning plates, and vent control on the stack......I predict there is a pretty good chance you will end up chasing your tail trying to "balance" the system every time you try to cook.

[FlightRN]

KMM, Are you saying that if i use a half moon cut out from FB to CC I don't put in any baffle? The standard offset cookers I have looked at had a baffle. When I used feldons calc it said for a round hole 14.08 in diameter or 155.62 sqin for FB to CC, I figured three 6in pipes would be more than that. Thanks for your reply!

[k.a.m.]

Are you wanting to cook the burgers on the reverse flow plate like a griddle?
As for the connecting pipes I would connect the firebox directly to the chamber with one opening and have the top of the opening where my reverse flow plate starts basically the plate is a continuation of the top of the firebox. I like my plate set at 4.5" below the top of the cooking grate with a 1" fall away from the firebox.
_________________
Always remember slow and steady wins the race.

Hybrid Cooker

[FlightRN]

[k.a.m.]

325° is about as realistic in a 250 gallon reverse flow as I would want to go. Much higher and you are really testing your firebox to generate that much heat.
_________________
Always remember slow and steady wins the race.

Hybrid Cooker

[k.a.m.]

No baffle between the firebox and cooking chamber.
_________________
Always remember slow and steady wins the race.

Hybrid Cooker

[FlightRN]

Thanks k.a.m.! We (our church) have been renting this crappy offset smoker here in town that doesn't maintain temps well and is too small. As of right now we do 3-4 big community events a year. I do ribs 10-15 racks/chicken at one and burgers (100+) hot dogs at the others. This seems to be growing and more and more people coming. Any experience with burgers and dogs truly "low and slow" ?
Do you add moisture pans under cooking grates?

Trying to figure if I need to add a grill to backside (might blow the budget) or if I can get by with just the RF smoker.

[FlightRN]

Here is a trailer my Dad gave me for FREE!!! Originally used to haul snowmobiles and ATV's. I was thinking of cutting out above tires making fenders and placing bigger tires on it?[/img]

[KMM]

Sorry for the delay getting back to you. A quick calculation shows the 3-6" pipes will only get you a total of about 77.91in/sq. (assuming .25" wall pipe).
As Kevin indicated, no baffle between fab and cc.
Based on your requirements, it sounds like you are needing more of a grill rather than a smoker? Luckily, that 250 gal tank can be configured into a kick arse grill. You could go several ways....split in half and make two santamaria grills, create a large cooking crate and configure charcoal trays on the sides, build a carousel tray rotisserie...the list goes on.
About the trailer....check the axels, I'll bet they are rated at 1500# or less. Unless you build nothing more than a couple cooking grates, I doubt there is anyway you will be able to keep a 250 gal cooker under 1500#. Probably should save the snowmobile trailer for another project and start browsing craigslist for a trailer with 3500# axels. Keep us posted on your progress.

[FlightRN]

Yep, I checked and it is 1500lb axle, You think the 250gal cooker will weigh more than that? figuring 480 for the 250 gal tank and 188lbs for the 50 gal propane tank fire box. thats under 700, everything else with grates, RF plate and chimney will weigh 800? Maybe I can use frame and weld new axle to it? Thoughts? I really appreciate all the help

[k.a.m.]

A 250 gall propane tank comes in around 700 lb. before modifying to a cooker. That trailer will not hold a decked out 250 gallon smoker.
We cook burgers on offsets all the time just run your temps up to around 300°
You could get a custom 3500 lb. axle from Red Neck trailers to fit it. Add new hangers and you're good to go.
_________________
Always remember slow and steady wins the race.

Hybrid Cooker

[KMM]

Also check the capacity of the ball hitch. Looks like the current one is bolted on? If so, swapping it out shouldn't be a big problem.
After spending a pile of cash and tons of time building, the last thing you will want is for the trailer to break loose while you are tooling down a hill and watching your beloved cooker pass you. (or even worse, get caught-up in a DOT check)

[KMM]

Just for giggles, can you post a pic of the tank you plan to use? I noticed the first time you mentioned it as a 200lb tank....then as the exchanges progressed, it morphed into a 250 gallon unit.
200 lb vs 250 gallon......given there is a fairly big size difference between the two...it is probably better to be sure we are all on the same page before you begin selling a kidney to buy all of the goodies and steel required to build. What say we take a peek?

[FlightRN]

Absolutely, I'm picking it up on thursday. Just to clarify the CC is a 250 gal tank, the FB will be a 200lb(50gal) tank. Got both for $200. plus free trailer i'm hoping I can get the pipe for chimney free from a friend and keep overall price down.

[FlightRN]

Just had one of my friends get back to me and he has a bunch of 1/4 in steel plate he wants gone......I humbly told him I could help Quality seasoned hardwood is really hard to come by where I live so I was planning on using lump charcoal (I use Cowboy alot). Does using charcoal have any effect on FB sizing? If I have enough pieces of the 1/4 in plate I am planning on just making a square firebox with warming rack on top.

[KMM]

How does a guy get a friend like that?
I wouldn't mess with the size of the fb based on current availability of fuel. Anyone with a friend that has a bunch of .25" plate he wants gone, probably has another friend with a grove of dying pecan trees!

[FlightRN]

[k.a.m.]

[FlightRN]