First down flow build Has been started

Discussion in 'Other Builds' started by scott s, Mar 18, 2015.

  1. Ok guys here goes.

    A dedicated DOWN flow smoker. I burned the tanks last fall and have been itching to get started all winter, the weather has started to break and my business (seasonal) is slowly getting going so if I can't get it done in the next few weeks it won't get done any time soon.

    Last fall I burned the tanks. On previous builds I just rolled them in a fire to burn off the paint. (with marginal results) This time I decided to burn them from the inside-out and it worked great except for one major problem. For some reason halfway through the burn they started smoking like a three alarm fire . I was able to cure that with a weed burner on the second tank but the cops and fire department showed up on the first

    burn and told me not to do it again

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    Cut big holes in both ends of the tanks and lit them up

    paint burning off nicely
     
    Last edited: Mar 30, 2015
    unclebubbas bbq likes this.
  2. Computer just crashed halfway through the post so hoping this shows up in order.

    Next pic is of the Smoke storm


    This is the second tank burn. I used a weed burner to ignite the smoke when it got bad.  
     
    Last edited: Mar 19, 2015
    unclebubbas bbq likes this.
  3. OK I figured it out and can just hit reply to keep the original try at a post going.

    here are the pics with comments underneath I THINK

    That's the brother in laws mitt next to the end of the tank I just cut off  wearing what he calls his welding jacket ( a flannel shirt that is in its self a fire hazard) . Click on the pics to get a better look.


    here it is with both rounded bell ends cut off and 1/4" plate tacked in place


    Trimmed off the excess with the plasma cutter ( big mistake should have cut the round then welded on)

    OK Weld and learn

    Good thing I have 25 years experience with a grinder to make up for my lousy welding skills

    Embarrassed to tell how long it took to make it look just decent

    OK this one wasn't necessary but it looks good and smooth

    Thought this one would be interesting so you all could see the roller table I found at the scrap yard.

    Started the fire box will post more later the computer is throwing a fit and afraid of a crash
     

  4. Cut the opening from the fire box to cook chamber.
     
    Last edited: Mar 19, 2015

  5. .Got the fire box on not real happy but I can work with it.

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    Pic from inside the fire box looking at the FB to CC opening
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    Layout for the FB door corners drilled in 1/8 inch so I don't have the dross splatter from a pierce cut on the plasma.
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    Decent cut looks ok needs

     minimal grinding and pretty square.

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    This tank will donate the door that will be cut an inch larger than the opening I cut in the CC in all directions
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    All cleaned up and ready to cut.

    .More tomorrow I hope.

    That brown "Post a Reply" box just to the lower left is for you to leave a comment or ask a question if you want.

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    Last edited: Mar 19, 2015
  6. I'm watching you have my attention

    Gary
     
  7. First I want to thank Gary for letting me know I'm not totally alone here.

    I do realize this is not a popular home build design though I found a couple sellers building down flow smokers.

    Since I am not a "Normal being" I plan to also show all my screw ups and what was involved in fixing them. so far I have a couple goodies. But for now ON WITH THE SHOW.

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    This is a wheel cut just before it let go. The next cut is the same using the robot weld as a guide to give me a strap I will show later

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    This is my method of getting a straight line on the side of a tank to cut the door.

    Finding a flat clean surface slide something known to be flat and straight tight against it and mark with a marker several times around the diameter. then do several measures to verify all the new marks erasing any that are not agreeing with the majority. then take a measure to your planned door opening and know your door will be straight and square.  I have tried measuring off the factory robot weld and been burned. As you can see in this pic the factory robot weld is distorted and NOT a good judgment line

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     This is the second band I cut off the end of the tank in the pictures a few shots ago.

    I used this to give myself a guide for the door cut.

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    .Got the last wall on the Fire box

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    Well ok it didn't exactly line up the way I had planned.

    I don't think I mentioned although this flat stock steel "LOOKS NEW" it came from my local scrapper discarded for one reason or another on its way to be melted down into recycled steel.

    Don't get me wrong I'm not bitching but this stuff is far from "NEW PERFECT" I trim around the real ugly stuff and use a sledge hammer to iron out the minor stuff but the price is right so I use it. Then cuss myself for being cheap all the way through the build process every time.
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    Picture above is first cut to open the door. the first six inches of it at the top are a garbage cut that drove me crazy until I figured out what I was doing wrong.

    I can't prove this and only know what happened to me, is that I had been using some real strong magnets to hold a guide in place while plasma cutting and going through tips like crazy prior to making this Freaked up cut. I believe the strong magnets pull the plasma stream and ruin the tip in the process if anyone knows for sure I am all ears.
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    This is a closer shot of the first six inches of the cut above you can see exactly where I changed the tip again and the cut smoothed out
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    Last edited: Mar 21, 2015
  8. Before RF's got popular, I'm quite sure a lot of people had doubts about them. Looks like you are coming along nice.  I'm still here

    Gary
     
  9. A plasma arc may be affected by magnets but it would take the type of electro - magnet you would find at a scrap yard picking up cars. Plasma is electricly charged ionized gas forced through a small orifice. And since gasses are not magnetic it would take a significantly large magnet to affect the electricity in the arc to throw off a cut like yours. Most likely your issues lie in dirty or wet air getting to the cutter tip or not changing you electrode and nozzle often enough or possibly dross from piercing the steel getting in the way.
     
    Last edited: Mar 22, 2015
  10. Interested to see how this one turns out. Looks like a beast so far
     
  11. Looking good! Nice to have a well equipped shop!
     
  12. OK I had a decent weekend in the shop got the CC door cut,  started on some hinges and worked on the chimney

    This is the upper door where the hinges will go.

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    Whacked out the door without stopping I was pretty confident that the thorough burn to get the paint off also relaxed the metal so it shouldn't pop when cut and wanted to test the theory since I don't plan to use the cut from the opening.

    Everything worked well and the door wasn't warped at all and could have been used if  wanted.

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    Pic taken just after the door was cut I tried using those magnets to hold it from dropping but only one held I guess nearly forty pounds is a lot to ask for a two inch magnet no matter how strong it is.


    Yep this is a hole in the side of a tube


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    Started on some hinges this was a trial and error thing. I still have the hunk of iron that I ruined while trying to figure out how to get the cuts done and will insert the pics as soon as I remember. These are the ones that worked the best.

    Using the ring I showed earlier as a template I cut both sides of the ring leaving the ends intact to keep it from warping.

    Notice the black line on the ring I used this to keep them centered and even. It worked just OK

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    .Sorry I skipped a couple shots but I get going and don't remember to take pics

    to get to this stage I drilled both ends of the hinge with 1/8" bit then clamped to the next one and transferred the hole to the next one.

    One at a time until they were all done then I put a small nail in to keep them all aligned and tacked them with the welder so the grinding would be easier.


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    .Next step was to the drill press using the pilot holes kept them all uniform


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    Last edited: Mar 23, 2015
  13. Got some more done

    Working on posting but the computer is acting up so I will post the pics now and edit as I can

    Got the FB door mounted need to get more pics of the door.

    Used a long rod to keep the hinges aligned so the door can be lifted off.

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    Outline for the chimney mounting block to be cut


    Start of the chimney mount

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    Cut the holes


    From inside


    Tacked in place.


    Main fresh air intake for the FB is on left side of FB wood loading door is on front


    .Full open


    Half open I have some questions about secondary air that a lot of guys are using with reportedly good results I will ask later.


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    .This is where I am so far. Little piece of the chimney checking to make sure it is fully open for air flow

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    Last edited: Mar 25, 2015
  14. Nice,  Looking better and better

    Gary
     
  15. This is crazy good!
     

  16. I have a question about secondary air flow for anyone with experience using secondary vents.

    Using the picture above my door is facing front, the FB intake vents are on the left end.

    What I need to know is if it would be ok to put the secondary air intake in the lower corner on the right side of FB below the CC?

    This FB is huge and I expect the fire to mostly be to the left rear area near the primary air intake.

    I guess I am asking if the secondary intake needs to be above the fire or just in a spot it will allow air flow without stoking the fire?
     
  17. bruno994

    bruno994 Master of the Pit

    Dave has always been a cheerleader for upper air intakes and after discussing it with him several years back I added one to mine.  Love it.  I will typically trim back my side intakes, which would be stoking the fire to maybe 1/8 open while the upper intake is 1/4 to 1/2 open.  You won't hurt yourself with it, because all you have to do is close it off.



    Great looking build so far.  Can't wait to see the end result, including some Q-view.
     
    Last edited: Mar 25, 2015
  18. Just a thought,  Not in the door but the side of the fire box across form the FB to CC opening  This way you will be able to control the heat and airflow better,   Mine is an RF but the top vent really made a big difference 



     
  19. Got some more done.

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    Door latch is on and works well



    Chimney is tacked in place for the second time.


    I wish I had made the mounting block for the chimney a lot bigger. That was an impossible weld. Its only 5"x5" the chimney is 4" OD so that doesn't leave any room. I had to remove the mounting block weld the chimney on to it then re tack it to the CC If I can't get a good sealed weld from the mounting block to the CC I can weld it from the inside.

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    Supports for grates


    3/4" angle Almost killed me to pay retail money for NEW angle iron 3/4"x3/4" x1/8"

    One 20' stick was almost $14.00  So far every piece is from the scrap yard except that. But it is pretty blue and no rust.


    Stainless grille grates 1/4" round rod. I didn't build them I just took three good used ones and trimmed to fit. A couple of the rods are broke free on one end and I'm  going to have to tack them back but have never welded stainless before. The guy at the welding shop told me that tri mix is not needed I can just use 100% argon (witch I have on hand) Any advice on this subject would be greatly appreciated

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    Last edited: Mar 26, 2015
  20. Nice build and good craftsmanship!
     

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