Henrik Yes, stack should be plenty big enough, it is 5"ID 1/4" wall and will be 3 ft. Lg. Don't need to preheat but in winter may help and my thought was flow would be better up from the bottom versus trying to pull across for the fire. Also wanted to eliminate the visual vents. Also I have used Feldons pit calculator for opening sizes. Mine is only an 80 gallon tank 24"dia.x 48"lg.
Can't wait to see your special touches.
Cool! As for air flow: it will pick the path of least resistance :-) If you need more draft, just make the stack longer. Diameter is fine. Nice touch to hide the visual vents.
Henrik Yeah I have a 5 foot piece for stack so I will adjusted as needed to get the proper length. My cook chamber opening will be at grate level and above so flow should be better from the bottom of the fire versus coming across the top to fuel the fire.
So, lot's of drawings being made, and material ordered. Got some nice super heavy duty cast iron weels coming soon, made to withstand 600 kilograms (1300 lbs) each. The wheel itself measures 6 inches in diameter. A bit overkill, but they looked nice. It was hard to find wheels that look 'old' enough. I decided to use swiveling wheels all around. Not that I plan to move the smoker around, but I will at least move it to its proper location, and every little bit helps.
The frame/leg stand is designed, keeping it simple. Will use square pipe, 2x2 inches.
Here's my firebox.
Yes, I'm prototyping using thick cardboard style paper. It is very much cheaper and quicker than welding :-)
I've switched back and forth between round and square, but settled on square in the end. The dimensions for this one is 60x60 cm, 70 cm long/deep. That translates to 24x24 inches, and 28 inches long/deep. The logs in the picture measure 12 inches. I will make an inner box for this one too, so there will be a 2 cm (0.8 inches) air gap. It will be air insulated in other words.
I probably will create a separate thread for this build. Now there's a two week wait before I can start welding the stand/frame, and then another week before I get the big tank transported home.
I will have a guy with a crane load it up on a trailer, specifically onto my (then built) frame/stand. That way I can roll it off when unloading (via a ramp). Wish me luck :-)
Henrik, Spinaker, I think your use of Cardboard Mockups (Proto Types) will save you much time and Make for a Better End Product! One Caution, You can Bend Paper to a Sharper Crease than Steel Sheet this can throw either your internal or external dimensions off? A simple Cad Cam program will allow these dimensions to be factored in! Foam Core Sheets of the same thickness as your steel sheet will allow you to Mock Up a Full Scale Model!
Eat Well and Prosper! From a Backyard Cremator in Fargo ND, Dan
When l saw the cardboard box l could'nt help but to think of our friend who was smoking a whole pig in a plywood smoker. Was going to suggest to you that ply wood would work better than cardboard, but then, you righted the ship in your explanation of what your are to do. Enjoy man!
So, here's another shot (1:1 size) of the short end of the smoker. I'm sizing up the legs here. The half circle is the propane tank, so the upper edge is where the grates will be located. As mentioned previously I'm going with square pipe, 2x2 inches. I've measured the height from the ground up to where the grill grates are, to get it to 36 inches (90 cm). That is the standard height for kitchen workbenches in Sweden, so I figure that should be about right for a smoker too.
The stand/frame
The wheels I've bought add 8 inches (20 cm) to the height, so my "legs" will be quite short, 16 inches (40 cm).
The leg stand will look like a table flipped upside down. I will use the area below the smoker as a shelf to store things.
The name
Well, many people give their smoker a name, and I figured why not? But I believe that neither boats nor smokers are a "she", they are an "it". Just to be defiant, I decided to swing the other way, and dub this one "rude boy", from Rihanna's song with the same name. I'm not a big Rihanna fan, but after hearing it countless times on the radio one line got stuck in my head: "Come here rude boy is you big enough".
I'm pretty sure we can all agree that it was brisket capacity she was thinking of when she wrote that line
Some rude-imentary smoker theory
Well, I will have to add more here later. Basically I believe the smoker is a system, where various parts interact together. One cannot isolate the stack by itself, just as you can't treat the firebox as an individual part. I also believe that the smoker needs to breathe well. In order for a smoker to breathe, it needs a big smoke stack. I've done calculations on air throughput (cubic meters/second) and decided to use an 8 inch stack. I haven't settled on exact length yet, but am aiming for roughly 2 meters (6.5 feet). A standard round steel pipe/tube will be used. All theory aside, I will look into the cost of chroming it, just because I think it looks good . Being a biker I think it will look even better when it starts to change color from the heat, just like chromed exhausts do close to the engine on a bike.
As for smoke stack placement: it will be smack in the middle. I do have plans to make it slide up and down, so I can tweak its position, but this is on my list of "nice to have's", so not sure it will make it into "production". I will experiment a lot more with how air is entering the food chamber, and I will cook a lot of bisquits to fine tune the heat distribution. Firebox - round vs square: I initially planned for a round one, but for various reasons switched to square. A square firebox means a lot more fabrication, but that let's me shape the inlet to the food chamber a lot better, so that's what I went with. I don't think the actual shape of the firebox matters that much in terms of thermodynamics. The opening into the food chamber is more important, as well as its location.
Last edited by Henrik; October 11, 2016, 01:09 AM.
The tank is 1775 litres, which translates to 390 imperial gallons, or 470 US liquid gallons. Can't ever keep track of which gallon you use, so pick one ;-)
I think Feldon's pit calculator is a great starting point, and as he states on the web page, provides general guidelines. I do however want a bigger smoke stack, considering I want more draught. Also, although I agree with the idea of building the firebox 1/3 the size of the food chamber, those recommendations hold true for the 'normal' case of building a backyard smoker. Once size goes beyond 'backyard' (whatever that is), I don't think you need to stick with 1/3, it can be smaller. If you build it smaller the only difference is that it will take longer to heat up, but once it is up and running you should have no trouble maintaining temp.
One thing I came to think of is to compare smoke stack entry hole size (where the air enters the smoke stack) vs the firebox to food chamber hole size. I don't know how these correlate (if at all) in Feldon's calculator? EDIT: I just checked, and it seems firebox opening is relative to firebox size. Again, a good starting point, but I'm more keen on syncing it with the smoke stack size. I will make sure the smoke stack entry hole is the same size or bigger than the firebox hole.
These are just my personal opinions on smoker building though. To each his own.
Howdy folks! I have finally gotten hold of sheet metal, so today I began constructing the firebox. Lot's of welding, spent a good few hours putting it together. Will continue tomorrow.
The shop, well organized
The cut metal sheets
Welding action
The inner firebox
Here you can see the airgap before putting the outer firebox in place
This project makes me want to hop on my Harley and ride over to your shop and watch the transformation. Thanks for posting the progress reports. Very cool build.
So, time to fabricate some legs/stand for the big tank. I use 2x2 inch square pipe as you can see, with plenty of reinforcements. The stand measures 150 cm long (59 inches) by 80 cm (31.5 inches). I figured I need to make it sturdy to support the weight.
The legs, finished. As you can see there are four plates, one in each corner. This is where the wheels should be attached.
The "pointiness" of the upright legs is because I want the big (round) tank to fit in there, like a cradle.
> Weber Genesis EP-330
> Grilla Grills Original Grilla (OG) pellet smoker with Alpha/Connect
> Pit Barrel Cooker (gone to a new home)
> WeberQ 2000 (on "loan" to a relative (I'll never see it again))
> Old Smokey Electric (for chickens mostly - when it's too nasty out
to fiddle with a more capable cooker)
> Luhr Jensen Little Chief Electric - Top Loader circa 1990 (smoked fish & jerky)
> Thermoworks Smoke
> 3 Thermoworks Chef Alarms
> Thermoworks Thermapen One
> Thermoworks Thermapen Classic
> Thermoworks Thermopop
> Thermoworks IR-GUN-S
> Anova sous vide circulator
> Searzall torch
> BBQ Guru Rib Ring
> WÜSTHOF, Dalstrong, and Buck knives
> Paprika App on Mac and iOS
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