PLANNING FIRST BUILD ( PICS NOW INCLUDED )

Discussion in 'Reverse Flow' started by sholmes, Feb 26, 2013.

  1. sholmes

    sholmes Smoke Blower



    OK, I finally got my plan and picture to come up.  I decided to just start a new thread now that i have the pictures working.  Here is a picture of the tank that i am planning to use for the main cook chamber and a first draft of the build plan. Has anyone built a smoker with 2 cook chambers to be used separately or together depending on how much meat you have to smoke?  Would it be possible to make this design work?  My intention is to use the smaller vertical smoker alone for everyday smoking.  I would like to use the horizontal cook chamber or possibly both cook chambers for large cookouts.  How would you figure the firebox size, exhaust size and length, etc.. ?  Opinions and advice would be helpful and appreciated.
     
  2. wtipton

    wtipton Fire Starter

    We you able to use the calculator that i posted on you last thread?

    Looking at your drawings I dont see why it would not work. You just want to make sure you vents and smoker stacks are big enough to accommodate both chambers.

    Keep posting pics as the build develops.

    William
     
  3. sholmes

    sholmes Smoke Blower

    I have looked at the calculators and i think that i just need to add the volume of both cook chambers together to figure firebox size and exhaust size and length.  Is there a problem with the fire box being to big when i am using only the small cook chamber or can i just adjust the size of the fire or intake openings to the smaller cook chamber volume?

    I have not decided what i will use for the vertical cook chamber yet.  I like the look of a round tank but making it square would be nice for shelves and easier to build. When i decide what to do i can try to figure the numbers. 

    Would an air compressor tank be thick enough to use for the charcoal grill or maybe even the vertical cook chamber?
     
  4. You need to use both cook chamber volumes to figure the firebox like you stated. The firebox to cook chamber opening needs to be calculated using both as well. The stack on the horizontal should be calculated using only that cook chamber volume and the total firebox volume. You will be closing it off to use both cook chambers, so the vertical will take the place of the stack. I am not sure how to figure that. I would think that if you used the same size pipe and made the stack on the vertical come up to the same height as the other stack it would work. When you are using just the vertical cook chamber the stack does not need to be much because the natural flow of the heat is up and it will draft easier.  I hope that was understandable. Kinda hard to put my thoughts into words sometimes.
     
    Last edited: Feb 27, 2013
  5. shoneyboy

    shoneyboy Master of the Pit OTBS Member

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  6. sholmes

    sholmes Smoke Blower

    SORRY THE VERT. COOK CHAMBER WAS SUPPOSED TO BE 30 IN WIDE, NOT 36 IN. I WROTE IT DOWN WRONG.


    I think i have decided to make the vertical cook chamber square instead of finding and using another tank.  I just think it will make things simpler and get me started faster.  I have taken some time and tried to crunch the numbers.  Here are some more plans and some dimensions.  I am not sure that i am doing all the math correct, i have never built one of these before.  If some of you who know more about this stuff could take a look and let me know if i am close or way off that would be great. 

     
    Last edited: Mar 2, 2013
  7. wtipton

    wtipton Fire Starter

    Question, why not make it simpler and have the smoker/heat go through the big tank then into the vertical box then out the smoke stack. I know you want to be able to use one or the other but the calculations and draft change for each one. if the fire box is too big for one then the draft would not be right and your fire wont burn correctly. plug each chambers dimensions in the calculator and find out how big a firebox you need for each one and see how close they are, if there is not to big a spread you should be able to make it in between. but if there is a large spread then a different design might be in order.

    Also a air compressor tank is perfect for a charcoal grill or smoker. I am looking for one myself.

    William
     
  8. Your vert cook chamber volume is incorrect according to the diminsions. 36x24x40 = 34560

    That would make the firebox need to be 28"tall which is not a big deal. The FB to CC volume changed to 290. If you put the top of the FB at 11.5" up from the bottom of the CC it will give you that size opening.

    You also will need an air gap between the vert CC and the FB. If not it will run real hot even without smoke flowing through it, and be harder to control the temps.

    This is going to be a very complicated build to get it all right. The idea of running the vertical without the horizontal is going to be the hard part to get right. I wish I could help more. Maybe someone else can. Good luck
     
  9. sholmes

    sholmes Smoke Blower

    RASIMMO,  YOU ARE CORRECT.  THE VERTICAL COOK CHAMBER WAS ONLY SUPPOSED TO BE 30 IN WIDE, I GOT CONFUSED WITH ALL THE NUMBERS AND WROTE IT DOWN WRONG.  I WILL TRY TO REPLACE THE DRAWING IF CAN FIGURE OUT HOW.  I HAD PLANNED TO BUILD AN INSULATED FIRE BOX.  WOULD THAT TAKE CARE OF THE AIR GAP ISSUE OR AM I MISUNDERSTANDING WHAT YOU SAYING?

    WTIPTON,  I WAS HOPING TO BE ABLE TO BUILD A SMALL FIRE BASKET TO PUT IN THE FIRE BOX WHEN USING THE VERT. CC ONLY AND CLOSING THE AIR INLETS DOWN A BIT.  I WAS HOPING THAT WOULD WORK AND WOULD USE MUCH LESS WOOD WHEN SMOKING JUST FOR A FEW PEOPLE.  MAYBE THE DRAFT WILL NOT WORK CORRECT IF I BUILD IT THIS WAY, MORE RESEARCH MAY BE IN ORDER.

    THIS IS EXACTLY WHY I AM HERE,  I HOPE TO GET THIS STUFF ALL WORKED OUT BEFORE I START THE BUILD.  THANKS FOR THE INPUT...
     
  10. wtipton

    wtipton Fire Starter

    Always a good idea to check first then build, I made that mistake and built a 55gal barrel RF that bombed hard core.. lesson learned.... looking forward to see how this progresses.
     
  11. You just need to make sure you have something between the FB and vertical CC to keep heat transfer controllable. Either and air gap or gap filled with insulation will be fine.
     
  12. sholmes

    sholmes Smoke Blower

    If i run an insulated fire box can i get away with it being a little smaller than the calculator suggest or do i need to keep the inside dimensions of the fire box per calculator?  I would like to use 1 in. square tube for the fire box frame.  Will 1 in smaller all the way around be too small of a fire box even if it is insulated?
     
  13. Sholmes i like your idea. Im throwing around an idea something very much like your design. My only added thoughts are baffles in the bottom of verticle smoker. I think it would help even the heat out. Also a dampner between fb and vert smoker. Good luck. Love your design
     
  14. sholmes

    sholmes Smoke Blower

    I finally had the time to go get my tank.  I opened the valves and maid sure that the tank was empty.  I removed all of the plugs and valves from the top of the tank.  I filled the tank with water and let it overflow for awhile.  I left the tank full over night and then dumped out the water and loaded the tank into the truck.  The tank, truck, and myself all smell terrible.  I put some bleach and dish soap into the tank then filled the tank 1/3 full with water.  I think i might drive around with it in the truck for a few days and let the soapy water slosh around.  Maybe the smell will get a little better.  I am still very nervous about cutting into this tank.  I think i might let it sit empty for awhile and start working on the firebox.

     
  15. When cleaning out my tank I got that oil on my shop sneakers and two months later they still smell something aweful. They smell bad enough the wife insists the stay on the porch.
     
  16. dutch

    dutch Smoking Guru Staff Member Administrator Group Lead OTBS Member SMF Premier Member

    SHOLMES-On my Lang, the warming box sits right on top of the fire box. There is no gap at all.  There is a separate steel plate that sits over the firebox-warming box opening that acts as a heat sink.  If I want to cook in my warming box, I just remove the heat sink and I can easily get my temps up to 350° while maintaining low and slow temps (235°-250°) in the main chamber box. With the heat sink in place and the baffle between the cook chamber and the warming box slightly open (about 1/4) I can maintain warming temps between 140° and 170°.

    The only suggestion that I would offer would be to relocate the baffle handle between the firebox/warming box-have it come out thru the side and not directly over the firebox opening.  That handle is going to get mighty warm when you open the fb door to add more wood.
     
  17. sholmes

    sholmes Smoke Blower

    A few questions.

    1.  I was planning to use 1" sq. tube for the fire box frame.  How thick?

    2.  I thought i would use 1/4" for the inside of the fire box and 1/8" for the outside.  Does this sound OK or is it overkill?  I do not want the fire box to warp or the paint to burn. 

    3.  What should i get for insulation?  How much does it cost? 
     
  18. We are using 1 inch tube and worked great. Your sheet metal plan for the outside and inside is rite on I think. We used 11 gauge inside and out with insulation but had slight warpage. We used rockwool insulation. Good stuff but kind of spendy. Sand or fire brick will work fine and is cheaper. Good luck and keep posting pics thanks rich
     
  19. jarjarchef

    jarjarchef Master of the Pit OTBS Member

    There are many opinions on how to prep a tank for cutting. The method that seems to be more used is what I have seen and helped do. Flush the tank a couple times with water, letting it sit a couple days in between. Some will cut it with water in it and some remove the water. I have used an electric cut off grinder, so the one I helped with we drained the water to below where we were cutting. We also added dry ice to the water and let sit for about 10-15 min before we cut it. It pushes the O2 out of the tank, so much less chance of a spark causing the "BOOM".........

    You will have a great looking smoker when done. I foresee many family gatherings with that being the star......... Thumbs Up
     
  20. 05sprcrw

    05sprcrw Smoking Fanatic

    The dry ice in the water is a great way to help displace the o2 and keep danger to a min.  The last cooker I made, I went with an old anhydrous ammonia tank instead, once its emptied and valves are opened. You can fill it with water and any remaining AA becomes inert and safe to cut without any issues. AA is very dangerous if your not used to being around it however so there are still plenty of risks with these tanks as well just not one that will go boom.
     
    Last edited: Mar 19, 2013

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