Rear-Facing Reverse-Flow Barbecue Trailer

Discussion in 'Reverse Flow' started by spankerchief, Apr 2, 2011.

  1. Hi there.

    I could use some help, and this looks like the place to go.

    I've been lurking here for a few days with ulterior motives (stealing ideas).

    It took me a few days just to get through enough of it to get a rough idea of what I want to do here.

    I had to correct a LOT of mistakes in my design.

    (Seriously, I didn't have a clue)

    Let me start with a little history;

    I work in the maintenance department at a prison in Taft, California.

    There was what you might call a legal "scuffle" between my coworkers and the management over some lunch hour issues.

    I stayed out of it, feeling that the really good pay  we're getting is enough to compensate.

    Regardless of whether or not I agreed, the guys won their case.

    So I'll be getting some money that I don't really feel right in taking.

    As it happens, during this year's in-service training we were told that the staff barbecue actually belongs to the inmates because some profits from the commissary were used to build it.

    The BOP doesn't want staff using it anymore.

    So here we are.

    This is my 7th or 8th remodel:


    I'm still tinkering with the stack(s), tongue and jack configurations, but this is the general idea for the chamber and firebox.

    I started out with a Harbor Freight trailer and a box that was wayy too big:[​IMG]

    I'll be cutting it down and welding it back up this next week when I start my vacation.

    In the meantime, I'd like to know;

    With the configuration and sizes as shown above(24"x24"x37" Chamber & 20"x20"x18" insulated firebox)

    Do you guys see anything that might cause me trouble on this build?

    -Aside from the stacks, which was my other question...

    I want to do twin stacks to make the smoke flow evenly. How do I calculate this?
  2. Well, this is gonna be a little patchy-looking since I don't wanna waste the steel, but at least my little torch kit makes unzipping it pretty quick and easy.[​IMG]

    I spent the whole day Sunday cutting and welding the scraps together into usable pieces and this is as far as I got:


    I called it a night at about 7:30, mostly due to this:

  3. fourashleys

    fourashleys Smoking Fanatic

    I hate it when the spool runs empty!! [​IMG]Spankerchief!! That looks like a fun little rig you got going there. As far as any calculations go just search the pit calculator and plug your dimensions into it. It will give you the numbers your looking for. I used it for my build and it has worked like a charm. Looking forward to seeing this one progress.
  4. Thanks Fourashleys!

    I used the pit calculator when I made this last design. There isn't a calculation for splitting the exhaust into multiple flues on either of the two spreadsheets.

    I'm still tinkering with the plans (as you can tell by the way some things are moved around from view to view).

    Anyway, I've got a new roll of wire and just picked up some steel and will be moving on to getting the trailer modded and the firebox welded up this weekend.

  5. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    I personally like the removable tongue idea myself. I hate beating up my shins!!!!!

    Great progress, and theres nothing wrong with not wanting to waste valuable steel.

    I noticed you said you work in the maintenance dept, you are probably already aware of the fact that. Unless you are a veteran welder that you should probably stay away from structual welds on the trailer frame/tongue with the 115 volt welder. 

    I have no idea of your welding skills, and I am in no way saying you don't have the ability to do it safely. 

    More so I want to make sure someone doesn't come along someday and read this thread, see the weldpak 100 and go to town building a trailer frame.

    It makes for a really bad day when one of these comes apart on the highway.

    Usually its not the driver that gets hurt, its the family driving the other way that gets it. 

    Sorry for the rant guys. 

    Like I said Great Progress, and thanks for sharing the pics. 
  6. bearcarver

    bearcarver Smoking Guru OTBS Member

    Looks like a great start from here!

  7. Okay, I know this forum is full of welders, so we'll put this to a proper test.

    I don't want it said that I led anyone astray.

    Here's what my edges usually look like:


    This is 3/16" plate BTW.

    This is my first pass up one side:


    Then the other:


    Here's both welds cleaned up:


    Now I notch it roughly in the middle:


    Do some cleaning with a file and sandpaper...


    And Voila!


    I've got some acid somewhere if you wanna see the grain...?
  8. Almost forgot the most important bit!:


    I hope this lays everyone's fears to rest.

    The Lincoln Electric Weld-Pak 100 with a .035 flux-core wire is a fine rig if you have a good ground, take your time and leave some space for fill.

    I highly recommend it for anything up to 1/4"
  9. tom37

    tom37 Master of the Pit OTBS Member SMF Premier Member

    I really wasn't doubting your skills. Honest! 

    And you are 100% right, that it can be done. 

    Like I stated in my post, I try to make mention for,

    1 the poster, incase they have just went out and bought a 115 mig  and went to town on a trailer. 


    2 that someone, some day down the road reads the post and goes to town on a trailer frame with no experience, failing someday killing someone.  

    All because they read it in a forum. 

    I have seen some pretty crazy stuff that guys thought was just fine, especially with a wire welder. 

    Anyways, enough said on that topic. 

    Where is your firebox going to be located? Underneath?
    jgwellwood likes this.
  10. fife

    fife Master of the Pit

    Cant wait to see the compleated prodject
  11. No sweat, Tom37. I didn't take it personal :)

    Your right to be worried about a novice welder doing any kind of structural work on something doing 70 on the highway.

    You can just as easily get a shallow, failure-prone weld with a stick or tig if you don't have practice.

    So anyone reading this should PLEASE DO THIS TEST themselves before attempting a project like this.

    No matter what type of welder you use.

    As for the firebox, it's forward of the smoke chamber with the door facing the tongue of the trailer.

    There's about 2-3/4 inches of overlap.(Just enough for the orifice between chambers)

    It's all in the first pic.
  12. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    SpankerChief, Good evening.

    most folks here are concerned about someone "reading between the lines" and not fully understanding the "safe" way to cure meat etc.

    Also, we keep an eye out on safety practices also on hygiene etc. Since you are a new member and we are unfamiliar with your work, newcomers may read sometning and take it as gospel.

    That being said, HOLY MOLEY!!!!! you can weld my stuff anytime. No porosity, the fracture test is pretty cool too.

    If you can smoke meat etc as well as you can weld, I'm signing up for classes. Just my "not so humble" opinion.[​IMG]
  13. Hah! Thanks Dave. :)

    I just started my vacation today, so the VERY FIRST thing I did was take a nap.

    Then, rested and clear-headed I wandered into the garage to start shortening the frame and took a long hard look at the trailer.

    -and found it leaving a lot to be desired.


    As you can see, it's made of thin sheet metal and a lot more holes than I'm comfortable with.

    So I chucked it and built this:


    I spent a good part of the day cutting the steel to fit together for the sake of rigidity and took care to weld it firmly:


    I'll build the tongue and fit the axle in the morning.
  14. bearcarver

    bearcarver Smoking Guru OTBS Member

    Your frame is looking good!

    That red one looks kinda like the little Red Flyer wagon I had when I was a kid, but maybe not as strong.

  15. [​IMG]
  16. Looks like you are getting it all figured out really well.

    Like that weld test you did.

    Your trailer frame should be plenty strong enough.

    Are you using the axle from the Harbor Frieght trailer?
  17. Yup. 

    In fact...:


  18. thunderdome

    thunderdome Master of the Pit

    I love these threads. Awesome work. Keep us posted
  19. fourashleys

    fourashleys Smoking Fanatic

    Love the progress. Look forward to seeing this one complted and Q-ing.:yahoo:
  20. scarbelly

    scarbelly Smoking Guru OTBS Member

    Looking good and like it is going to be a nice rig

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