planing to build a reverse flow in australia (virgin build)

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aussiq

Smoke Blower
Original poster
Apr 8, 2016
137
16
australia
Hi every one. My names ben. There are a lot of first for me. Such as this is the first forum group ive ever signed up to and First ever reverse flow build. I have never even seen a reverse flow smoker in australia ive only seen pictures on here so i need as much guidance as i can get and what a perfect place to get it. Well this is just a introductory post to get started. Give me a hr or 2 and ill put up my calculations (froms dave formulas) iam planning on ordering all flat plate from laser cutters so i need to get all the drawings right first (the boring stuff ) but iam good with the camerera so i promise lots of photos when the build starts hopefully soon.
 
Here is my calculations

Inside length 47.086
Inside diameter 23.149
Vol cc 19817.422
Fb/cc opening 79.269
Fb vol 6539.749
Air intake 19.817
Esv 435.983
Diameter of stack 4.015
Lenght of stack 34.4 but ill make it 36
Segment area 79.539
Segment hight 5.65

Iam going to make the fire box out of 5/8th thick steel

And i was thinking of 1/4 inch or even 5/16. Price is pretty much the the same so do you think its worth going to the 5/16?
 
Your numbers look good.....   If you have something to lift that hummer.....   5/8 and 5/16..... no one and I mean no two guys will run off with it...   It will surely hold heat well....   won't rust out in our lifetimes....   and when Armageddon happens, you can hide behind it...  Sounds perfect to me... 
 

I have this 90 degree bend that i was planning to use for the stack exiting the cc. Ive just discovered a previous post i think from dave saying that 90 degree elbows can restrict flow. Is that comment refering to home made elbows? Would this bend fine to use? As far as stack placement to the cc there seems to be quiet a few different ideas to where the stack should exit the cc. My plan was to use this bend and have it inbetween the top rack and the cc. Or i could have it inbetween the top and bottom rack. But my thaughts are that it will flow better if the exit is up higher ie inbetween the top rack and the cc. But it seems some people have the exit as low as the bottom rack but wouldnt this cause smoke to become stale? And if i mount it at the top of cc wouldnt it flow too good thus leading to a cooler cc Am i just thinking about this too much. Iam really intrested in hearing peoples thaughts from both sides here
 
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Maybe scrap that last post. Seams like a plenum is the way to go. Which leads me to... does a plenum need to be a certian shape? Or volume? Is it pretty much a fancy square box.? I really have no idea. The 90 degree bend idea sounds easiest but from the info i gathered on here i should avoid using the bend
 
Thanx smokejumper. I guess the location is just a matter of what looks good. Ive just about worked everything out now. Ive spent hrs and days going through all the post. Ive had pen to paper and i just have to draw everything up to send to laser cutters. I know sounds lazy , but less time i spend building more time i spend on the bbq. I cant wait to post some pics i think you guys and gals will be impressed. But give me a week or 2 to get started
 
I finally got my 5/8 thick plate for my fire box today. I even got motivated and half made it. Your not wrong dave this sucker is heavy i will weigh it and let you no once i finish it. I havent done the door yet and yes i will be putting vents opposite the opening. I made it 4 inches taller then it should be i worked my volume out from the top of the fire grate. So i will be putting the fire grate 4 inches up from the bottom. I allowed this extra space for ash collection. But ive worked out my air vent opening to the full volume of fb. I figured if its too much you can always close it down
 
Looking good already Q.

Where about's from OZ are you from? I'm in W.A and am also about to start my build. Just finished my calcs actually so was going to post soon. By the looks of your numbers tho mine is going to be a lot smaller.

Look forward to following your progress. Good luck!

Bazza
 
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Hey Ben,

Just a quick one. Have you sourced your expanded metal for your grates yet?

I have always used stainless mesh as I could only ever find galvanized expanded metal here. So I was wondering if you have found a supplier for straight up mild steel as I'm also in Perth. 

Bazza  
icon_smile.gif
 
I havent got it yet but go to midalia steel they have it but they have to order it in should only take a day or 2. What size are u getting? I was thinking about the smallest one.the next one up seamed a bit thin. But the next size above that looked ok. They had small samples in the shop. We could of just gone halves in a sheet but iam going to do 2 racks and a lower wood rack so i would need close to a full sheet anyway. Its cheap anyway think they said it was about $85. Get back to me on the size your getting i would be intrested in knowing
 
Iam real close to moving onto the next step. For my sized smoker i will be building , the calculation recomended 4 inch i/d 34 inch long oam happy to go with this. But i have both 4 and 5 inch I/d pipe. Iam leaning towards using the 5 inch pipe at the same hight as iam hoping it would flow better. I would love some persuasion from other people experiences as to weather or not i should go with the 5 inch pipe. I really want to get a move on so i can post some pics up for yas
 
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