After scouring the internet for design ideas I ran across this forum. I found alot of useful information but I still have a couple of questions that I was hoping someone would be willing to help with. I am planning on using a food grade 55 gallon drum as the frame of my cooking chamber. At this stage of design my two biggest questions revolve around metal thickness. If using a reverse flow design how thick should the metal be for the deflector? Is a tight seal necessary for this to be effective or would a decent fit and the weight of the steel be sufficient to redirect the heat. Secondly I am having a difficult time with material thickness for the firebox. I have read everything from sheetmetal to 3/8" plate. Would I be incorrect in assuming I can use a sheet metal, say 14ga, for the box as long as I have it insulated? what is the typical insulation used? I am a blacksmith and there are several insulations used in our forges, but I believe that they would be overkill for this application. There will certainly be more questions as the design nears completion, but thank you for the information I have already learned from the forum and I hope to learn more.
Embarking on a Smoker Build
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The firebox ( to me) is the heart of the smoker. It needs to be durable to withstand years of high temperatures with out warping, it needs to seal well in order to have good control over your temperatures, and it needs to have enough insulation to keep from radiating the heat through the walls and allow you to direct and utilize this heat in your cooking chamber.
Build it to the best of your ability!
You should follow Ribwizzard's advice on building a firebox. He's one of the grand masters at the art. Otherwise, if you want, you can try to use a second drum as your firebox, if you have access to one. Make a double barrel smoker, firebox on bottom with top drum as your CC. Exhaust pipe running up into CC. Then you can install a baffle plate to direct smoke as a RF. There's several pics of those you can find on here for visual.
, if you have access to one. Make a double barrel smoker, firebox on bottom with top drum as your CC
I believe that is a very effective design if you have limited access to welding cutting tools. I have never built one, but know people who use them and they seem to work very well. Could probably build one in a weekend.
Would 1/4" Plate be sufficient for the inside of the firebox and the baffle? I am still having difficulty finding what is used for the insulation between the inner and outer layers of the firebox and how thick should it be applied? Kaowool is what we use for gas forges. If 1/4" will suffice for the inner layer what should I be looking at for the outer layer? 12 or 14 ga sheet? I may end up going with the double stack design just for simplicity. I have access to barrels so that is not an issue. I thank you both for your incites so far.
Im in Florida, so I dont use insulation, just double plate the top with an air gap between plates, but if I were to insulate one, I'd probably go 3/16 plate for inner and outer shells. Non insulated, up to around a 24 inch firebox, I go 1/4" plate for everything.
The more I look at the double barrel builds on here the more I am liking them. One question I still have is how do most horizontal barrels do their hinges? Most pictures are with the door up so it blocks the view. how do people work around the 1:1 ratio of firebox to Cooking chamber using two barrels?
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Hello Mr Crazzy.... Where are you located? I read where you were thinking of insulating the FB, I live in Alaska so I really dont have a choice. My inner FB is 1/4in then an inch of insulation then I will cover with the outter skin. I will be placing it on a trailer so I can move it around the yard but this winter I will keep it beside the fire pit.
I am in Ohio. I am beginning to realize I was misinterpreting the definition of insulated. When I think of an insulated firebox I, being a blacksmith, think of the 2" of kaowool all around a gas forge. Looking at the designs I am seriously converting to the double barrel design. Is the vogelzang kit worth getting or are there better flue options out there?
I assume you are talking about northern tool? I can find the kits on their site, and the dampener by itself, but not much for as far as flanges. To my eyes the kits dont look too bad, but even buying both of them I will still be short one flange.
Your talking about the flange for the top barrel or cooking chamber door, right?
You could either buy some flat bar at home depot or If you can get an extra barrel, and cut the door out of it ( cut bigger so as no flange needed.)
The part I am talking about is the piece that attaches to the barrel and holds the pipe in place that connects the two barrels. Around the door on the cooking chamber I was anticipating using a piece of flat metal and welding it to the door to create the overlap required. I really appreciate your help on this. Without you, I am pretty sure I would have given up already.
Go to UDS builds and check out
And many more builds, there are tons of them,.
You can purchase a flange individually from there, I believe, but also Grainger should have some, or similar. Can also make one yourself. You'll see in most pictures, they have the flow pipe more to one side of the two barrels (usually the back side, away from the FB door). The ones I've helped make, we've put the flow pipe in the center. Then, in the CC, we put the RF plate centered as well, causing the smoke/heat to come out of the pipe, then travel to either side of the plate to reach the grates where the meat is. Like a RF, the plate heats, then the smoke comes around. On these that I'm talking about... the exhaust was put in the rear center, so that the smoke has to exit center, assuring it touches the meat. Hope this isn't too confusing. Have a drawing if you need.
is there a calculator, or a common answer, for how large the inlet from the firebox to the CC need be? It stands to reason that the diameter be much smaller than with an offset setup since it will be directly below the CC. Is one larger pipe towards the end work better than two smaller ones? Please forgive me if I intrude but doesnt your design smoke break cause a temperature differential between the left and right sides?
Feldon's calculator is the one I used....guess everyone does. Can google that, or look up member Dave Omack and see the link on his signature line. On the double barrel smokers I've helped with...there hasn't really been that much of an issue with temp differential. Saying that.... I don't personally own that smoker.... just helped a friend build a few. I've never heard any of them say anything about that problem, and the times I've been around them while smoking meat...there hasn't been a huge differential...no more than what you would see on the two ends of a larger smoker tank smoker.
BTW... One of the guys places a water pan on the bevel plate in the center, so that might help as well.
I was under the impression that Feldon's was for offset builds. Looking at it again I can see nowhere it says that so I appear to be wrong. the calculation I was questioning was the need for a 11.5" firebox to cooking chamber pipe. To match that kind of square inches I would need two 8" pipes.
Let me clarify my opinion on the Double Barrel Smokers.
When built in the configuration as in the pic below, I think it is a fine smoker. This is what I consider a true Double Barrel Smoker and I feel its an effective design. Some people get the ideal to try to make a reverse flow smoker out of them by adding a plate to the upper drum, I dont understand why, it is the original reverse flow smoker!