Advice needed reverse flow smoker build

Discussion in 'Smoker Builds' started by cornbread, Feb 15, 2014.

  1. Hi I have been working on a new smoker. I want to build a reverse flow. I have started a little of everything but I have some questions about the RF plate and the FB. For the plate I am planning to put the angle in the middle for the grease drain. Should the plate go straight across and tip the trailer to drain or should it pitch downward? I know you are supposed to be able to raise the trailer up and down to help with temps also should the plate start out straight from FB all the way across or should the first 8 or 12 inches be higher up and bevel down like a baffle type style? Should the FB have a damper at the RF opening? Also the FB air intake is it better to have air intake at the bottom or at fire level or both? I am putting some pics of what I have worked on any input would be greatly appreciated






     
  2. nick v

    nick v Smoke Blower

    That's a damn nice trailer for a smoker! Rectangular tubing all the way? That's not cheap. What's the two boxes for? Bottom a firebox and top a warming box? Which tank did you decide to go with? Looks good so far. I can tell you pay attention to detail like me. I smoothed out my corners also. You have a fab shop or something?
     
  3. crazyq

    crazyq Meat Mopper

    if you make the FB to CC opening the right size you wont need a damper to open and close. one less thing to adjust and have to worry about. I put my reverse flow plate at a slight slope so while I'm cooking the drippings will tend to gather at the drain end and I can drain it if needed during the cook without having to adjust the tongue of the trailer any. typically you want the air inlet to be mostly below the grate level. the incoming air needs to get to the bottom of the fire for the fire to burn right and draft correctly. I generally make mine half and half that way air under and over the grate.
     
  4. yes its rectangular tube I actually got it cheaper than angle. It was $175.00 for 3 stks 24-0. The box is a firebox and warming box combo and the tank I rolled from 1/4" steel it is 3-0 dia x 6-0 long
     
  5. Thanks Crazy Q I did get my measurements from the pit calculator so I guess the sizes will be close. I figured what you said would be the best way but you see so much on here its hard to tell what to do sometimes. Is it better to have 1 flue or 2 shorter ones it seems like 2 would draft better as long as you got the same or more volume from the pipes. as far as the RF plate should it be flat all the way across the length of the cooker or is it better to have the plate starting at FB opening bevel downwards a little bit  and then flatten outI have seen this on some RF smokers and am not sure what the purpose is except to get the heat moving faster through the tunnel
     
  6. crazyq

    crazyq Meat Mopper

    I laid mine in the cooker flat then used my jack to push down on the center to give it a sunken center then welded it in that way the liquid will naturally run the drain.

    Wether you use one stack or two smaller the total volume of the exhaust is still the same. Too much volume and the air leaving the pit will cool before its out of the stack and hurt your draft. Too short and itll hurt the draft as well.

    Keep in mind the pit calculators are just guides to building a good cooking smoker.
     
  7. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Since you have the shop, build a RW drain pan......



    Is it better to have 1 flue or 2 shorter ones it seems like 2 would draft better as long as you got the same or more volume from the pipes


    The stacks are a chimney.... when designing a chimney, height is critical for them to work.... they work on "differential pressure" to create air flow....
     
    Last edited: Feb 16, 2014
  8. Ok thanks that makes sense. Not sure  about the height of the RF plate from bottom of CC and distance to cook grate
     
  9. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member


    What is the size of the CC..... Have you cut the FB/CC opening ??
     

  10. I tried to make a drawing I guess I am asking if the RF plate needs to be like drawing 1 or drawing 2
     
  11. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    I would go with drawing 1.... drawing 2 will create an impingement/choke point for the heat to hit and become a hot spot... The draft through a smoker is convection and it doesn't have "force" like you would have with a fan.... When you choke the flow, it slows.... and then the FB heats up...
     
  12. The CC is 36x 72 and I have not cut the FB CC opening yet. I wanted to get it on the trailer and double check my math on how it is going to sit. Measure twice cut once.
     
  13. Well I finally received my axle and wheel kit. Hopefully I will be able to finish the trailer this weekend. I got some shelf supports in the warming box and decided to put a double wall in the FB. Hopefully everything I am reading is good and it will help with the heat retention and be more efficient. It seems to make sense. I decided to go with a 250 gal propane tank for this one instead of the cylinder that I rolled. I think the curved ends being on there will be easier to deal with and make the smoke flow easier. I guess I will build an offset from the other one later. The tank was drained of the propane and cleaned with dish soap and water twice. I filled it completely up to push out the air and remaining fuel. I filled it the last time completely full and scored the cuts almost all the way through with a grinder and 6 inch cut off wheels. I finished the cuts with a sawzall  The water came rushing out and had no problems. I was nervous because we had about 80 gal of propane in there 2 days before but it went smooth just have to be patient on the cutting. I burned a half of a truck load of hickory and pecan in there to help remove the smell and the paint on the tank. It is coming back Monday from being in a burnoff oven and media blasting. Hopefully gety some more pics next week.
     
  14. I got the tank figured out and the mounting brackets made. Seems like it fit pretty good. The axle kit is on and the trailer tracks nice. The Media Blaster did a good job on the tank very clean.
     
  15. I took the weekend and had a Birthday party for my wife. Built this cooker about 15 years ago. It is a gas and wood combo. It works pretty good has always been dependable





     
  16. nick v

    nick v Smoke Blower

    Looks good man. What's your plans for the space in front of the trailer?
     
  17. I'm not sure if I should use it for cooler storage or try to put a sink or a stainless table. Kind of hard to decide.
     
  18. nick v

    nick v Smoke Blower

    Probably enough room for both if you wanted.
     
  19. yeah I did some measuring today I think I can do both. Have to figure out how much its going to cost these things start getting expensive if you go crazy on them. But I have built a few and regreted not doing certain things.
     
  20. Got the flue on could not finish welding I cracked my shield inside the tank I guess I am too fat to get in there good

     

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