Need help thoughts and inputs

[William conner]

My name is William from Ohio I am building a insulated single chamber offset smoker from two 55 gallon drums open end welded together the stand will be 1 inch square tubing on wheels the grates 1/2 square tube cooking grates with diamond cut mesh I need help with fire box size and chimney size for good air flow thought about 3 inch exhaust pipe and how tall the chimney will be mounted on flat bottom side of barrel and fire bow on other side

 

[dcecil]

Welcome To the forum William. There is a thread in the forum about pit builds. Look through there and see if you can get some answers. Someone with build experience will see your post and I’m sure they will get back to. Good luck with your build and look forward to seeing pictures along the way

 

[motolife313]

1/2" is pretty small I'd go 1" and 4" exuast

 

[William conner]

1/2" is pretty small I'd go 1" and 4" exuast

I was going to use three inch exhaust pipe my main concern is how big of a fire box for 110 gallon smoke chamber with two racks the half in I was going to make the racks out of with diamond cut steel mesh

 

[1215]

Start here:

http://www.feldoncentral.com/bbqcalculator.html

I've seen people go back and forth that the calculator I linked isn't accurate. Rule of thumb is you want your fire box (FB) to be roughly 1/3 of the size of your cook chamber (CC).


Only other thing I'd caution you about is that 55gal drums are SUPER THIN. I'm building an insulated drum out of 55gal drums now. How are you going to deal with the fb? Are you going to build a fire basket and set it on grates? You really don't want the fire directly on the 55gal drum. Metal is too thin and will hurt air feeding the fire.


You said you are going to weld. Do you know how to weld? If yes then good. If no then I sincerely caution you about buying a cheap (inexpensive and poor quality) flux core welder.


Go look at something like a Gateway Drum Smoker. I don't know the exact specifics but they say to just leave the exhaust open and set each intake vent to 1/4" open and it'll give you a rock solid (I forget, maybe 225 degrees) for hours. Better to have more capacity (intake and exhaust) and be able to close it down than go through all that work and have not enough.


P.S. Welding 55 gal drums sucks. I'm doing it now. I welded my support structure and everything big with a GMAW (mig with gas) machine and now I'm dicking around with GTAW (TIG) to get the thin drum metal sorted. I can't imagine welding that crap with flux core or even mig with gas. Make sure your surfaces are CLEAN or it'll spark and splatter like crazy.

 

[1215]

Wait I just saw your other thread from May 15th. (the one with no replies) Are you trying to weld TWO 55 gal drums together to make one giant, long sausage... then you want to weld a side firebox to that?

If that is your plan I would consider revising and looking at other options. How about this:



Yes that's a chair in the shop/garage. A little wipe of acetone and it's a free whiteboard. Funny, you can see the acetone in the pic. You should go buy a few gallons of acetone. Clean and wipe down everything with acetone before you weld it. It'll make life easier.


So 110 divided by three is 36.666666666666 which is pretty darn close to a 35-gal drum. Just saying... If you did something like the contraption I drew out on the chair I'd use minimum 6" hvac ducts. Make sure you get non-galvanized because you can't weld galv. Well, you can... but it could significantly shorten your life.


I don't think you need 1" square box tube for your cook grates. Scratch that. 1/2 " for your cook grate supports will be fine. Consider using angle iron and welding it to the sides of the drum so you can slide the grates in & out. Will make it easier to clean, check temps, place meat, etc. 1" box tube for the legs and wheels may be a bit small These things get heavy. If you want to use 1" for that make sure you have adequate bracing and support. Even if you build a cabinet below the cooker/firebox to store crap (chimney starter, oven mits, etc.) the side panels will greatly strengthen the legs. Use BIG wheels. If you don't want to buy casters you can make wheels easy, just weld two pieces of angle iron together to make a U then drill it and put a bolt through it as a wheel axel. Easy. If you are going to weld two 55gal drums together you can figure it out --use big wheels. Like 6" big. Really big.


Good luck!


I'm sorry if you know how to weld and I sounded like I was talking down to you about welding. Nobody in their right mind would want to weld/work with 55gal drums. So I assumed that either you are as dumb/crazy as I am (and you know how to weld) or you don't know how to weld and you are headed for a massive challenge/learning curve. If you don't know how to weld I would strongly suggest considering a square/rectangle shaped FB and CC with heavier gauge steel.


Best,

 

[motolife313]

Make the fire box 1/3 the size of cooking chamber and that will be plenty. My design is similar to yours. U may have some uneven cooking temps in there becuase I got 2 different intakes. Becuase one of the tubes will likely flow better wich means it will pull heat better in one of the chambers. So u will have to play with the fire. Me I start my fire on the left side of my fb the couple hours in move the fire more right center. That's why I always have my oven gauges in my smoker. But if u make them really even and same length it shouldn't be to bad