ok....a few more questions before I start

Discussion in 'Reverse Flow' started by ballagh, Jul 7, 2010.

  1. ballagh

    ballagh Smoking Fanatic

    Just want to make sure i have all my ducks in a row before i start into this. Ii am almost done with my shopping phase and ready to hit it. Ii have been doing alot of reading on here and finding lots of great tips.  Just a few things I want to make sure about....

    1.  Are two 4" stacks going to be comparable to one 8"?  Striking out on my 6" idea, and there isnt a option for two stacks in the formulas.  Guess I should have payed better attention in school :)

    2.  Am I going to be ok if I slope my reverse flow plate towards the firebox and also slope it from both long sides towards a piece of angle iron (as a channel) to a drain tube then goin gdown in front of the fire box out the bottom of the smoker?  Talking a 1/8" fall per foot.  Not sure if this will mess up the smoke rolling over to the grate/food side of the smoker.  Dont want the smoke to funnel to the sides and not the middle.

    3.  Do you forsee any problems if I place my two stacks about a foot apart on the firebox end?  Bottom of the stack even with the top of the grate right? I hav eseen several different ways of exiting the smoker, going out the top, out the side etc...  I am wanting to put a empty keg on top of the firebox and cut a hole in it to use as a warming oven.  Hence the foot apart spacing of the stacks.

    4.  Are piano hinges the way to go?  Planning on two doors opening pretty much the width of the smoker with no divider.  What hinge does anyone recommend?

    5.  When figuring and cutting the firebox/smokerbox connecting opening...I am planning on 6" tall from the bottom , do I cut the horizontial line the entire width of the firebox or smoker box? (Or which ever is the entire length of).  I cant figure out the half moon forumla. 

    My brain is fried

    That is it for tonight :)

    Thanks for your help
     
  2. matts

    matts Smoking Fanatic

    Ok, I will give this a shot.

    #1. Common sense would make two 4" pipes equal 8".  I would guess the same.  But, if it technically isn't, I still don't see any problems since you actually only need 6" of exhaust.

    #2.  The slope has been debated before and it really doesn't matter.  Especially if your slope is only going to be that shallow.  Most RF plates are built the way you are talking with the two sides sloped into a piece of angle which drains out a tube.

    #3.  I think if you are going to use "duel exhaust" then it would be best to spread them apart like you mentioned.  It will theoretically draw a more even smoke flow across the grate.

    #4.  When I think piano hinges, I think a small hinge in a long length.  To me these won't be strong enough or last very long.  There are many stronger store bought options out there that will be cheaper or even make your own with some pipe and round bar.

    #5.  Cut your tank first then fit your firebox into the opening.  Use the tank and scribe a line on the firebox as a guide to cut.  Are you mounting the firebox flush to the outside of the tank or are you cutting into the tank a bit to fit the firebox in?

    Hope that helps.

    Matt
     
  3. ddave

    ddave Master of the Pit OTBS Member SMF Premier Member

    It's not even close.  Using the formula for area of a circle where

    area of a circle is pi * r² , pi is equal to about 3.14 and r is the radius of the circle

    two 4" pipes gives you 25.12 square inches and one 8" pipe gives you 50.24 square inches.

    One 6" pipe would be 28.26 square inches.

    Dave
     
  4. matts

    matts Smoking Fanatic

    wow, I stand corrected.  Crap, that means I need to add another pipe on my smoker.  Dangit

    Well at least I was right on part of my statement.  I still don't see a problem if he is a couple square inches off.

    Now, how the heck am I going to add another pipe on my rig??
     
  5. ballagh

    ballagh Smoking Fanatic

    so...does this mean in the calculator I should put in 4" for my pipe, and then cut the pipe length in half if i want to use two stacks?  I cant see using a 8" stack on this.  it gives your volume needed and you put in your pipe size, then it spits out your length.  so if you split that in half would it equal two pipes?  i need to order them tomorrow :(
     
  6. matts

    matts Smoking Fanatic

    What does the calculator say your need for exhaust?
     
  7. ballagh

    ballagh Smoking Fanatic

    1411.2 cubic inches

    112.36 inches for a 4" flu

    so two stacks take that in half????????

    2 - 4" x 60" stacks cover it?
     
  8. ddave

    ddave Master of the Pit OTBS Member SMF Premier Member

    Maybe you don't need to.  How does it cook?  Don't let the numbers dictate what you do if you are happy with the way it is cooking. [​IMG]

    Sometimes we get all wrapped up in the numbers (time, internal temp, etc, etc) and forget to judge effectiveness by the end product -- texture taste.

    Dave

     
     
  9. matts

    matts Smoking Fanatic

    Dave, Hard to tell so far.  Only cooked on it once.  But it worked and food was great.  So who knows so far.  I have a few modifications to do to it so I will have to see what happens next time.

    ballagh,  you lost me on that.  does it say to use a 6" exhaust?  Which calculator are you using?
     
  10. ballagh

    ballagh Smoking Fanatic

    using the timplate bbq form sq firebox.  i got it off someones sig on here.  It gives you the volume needed already and you put in what diamater pipe you want, then it tells you what length is needed to get your volume.  this is what i am going off so far unless there is something better out there?
     
  11. ddave

    ddave Master of the Pit OTBS Member SMF Premier Member

    Sounds like it's fine . . . for now. [​IMG]   I know it's hard to resist tinkering.

    Dave
     
  12. ballagh

    ballagh Smoking Fanatic

    So I was at northern tool and equipment today getting prices on trailer parts to build it, and noticed a ad they had.  I can get a 5'x8' trailer frame with everything but the floor for $399.99 and they have them in stock.  Seemed sturdy and pretty nice.  I am thinking by the time I buy all the pieces,parts, time and labor I will be money ahead by getting this one from them.

    http://www.northerntool.com/shop/tools/product_200356494_200356494

    It is only $399 in the store, not sure why it says $499 on the website....(Must be the free shipping that makes it more :)

    Anyone bought a trailer from them?  If so are you happy with it?

    Also went into the BBQ store today, he had thermometers on sale for $12 each, and looked at propane assist parts for the firebox, and he told me just to bring the smoker in and we could grab all the parts and take them out to make sure they will fit and be the right lengths and sizes.  How cool is that, probley save me a trip or two in there.  :)
     
  13. duck killer 1

    duck killer 1 Smoking Fanatic SMF Premier Member

    something i noticed while browsing around is the calculator is designed to allow for a HOT fire. if you are running lower temps say 225* all the time you prolly won't have a problem. hence the need for a flue damper to balance the draft.
     
  14. duck killer 1

    duck killer 1 Smoking Fanatic SMF Premier Member

    sounds like a good deal to me! since it doesn't come with a floor that gives you the chance to beef it up if ya think you need to. good luck!
     
  15. matts

    matts Smoking Fanatic

    I forget, are you using a fuel tank or a LP tank.  I think fuel tank.  If so, I think that trailer will be fine.  You will have a hard time building one from scratch at that price with time and material.
     
  16. ballagh

    ballagh Smoking Fanatic

    Yup a fuel tank for the smoker, and a 120 square fuel box for the firebox.  Propane assisted.  I am having a hell of a time finding stacks now.  Looking like $140 for custom made 4" duals, or about the same for a single 6" with fittings.  Trying salvage yards on monday.  Try and do some picking :)
     
  17. ballagh

    ballagh Smoking Fanatic

    and duck on the floor, probley just do expanded everywhere except for under the smoker.  just leave it open.  dont really see a reason to have a floor under it.  that way i could access the 1" ball valve under there for draining the RFP. 
     
  18. ballagh

    ballagh Smoking Fanatic

    So today I ordered the handles from KCK.  I got the 6"  stainless handles, I ordered a keg tapper handle from Widmer for the Warming box door handle :) and i found a really cool metal steer to weld on the top of the smoker.  Going to get the trailer this week, and should start very soon.  Still trying to find a deal on stacks.  Right now I have a few choices but try to figure what will give me the best bang for my buck.  Stay Tuned :)
     
     
  19. ballagh

    ballagh Smoking Fanatic

    Jackpot on the stacks today.  Drove by a semi parts yard and saw a assload of stacks all over the place.  I pulled in and talked to the guy, he said the city was forcing him to move so he was happy to sell off some stuff.  I picked up a pair of 5" chrom stacks in decent shape.  Just needs a little polish on them and they are golden.  $60 for the pair :)  He has to take them off the rigs and I will pick them up tomorrow.  Happy camper today :)
     
  20. raptor700

    raptor700 Master of the Pit OTBS Member

    Chrome stacks....... Hmmmmmm (sweeeeeeeeet)
     

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