100 gallon Silent Hunter build (lots of pics)

Discussion in 'Reverse Flow' started by silenthunter, Jul 26, 2012.

  1. silenthunter

    silenthunter Fire Starter

    My build will be a patio build with a 1947 100 gallon propane tank approx 23" x 62" x .28". The fire box will be 22" wide to fit the cut in the tank x 20" x 20" x .25". This will be my first smoker build and I plan on doing  plenty of pictures to go along with it. I am also going to try and put a lot of how to info, to make it easier for someone else to build their smoker.

    My wife, let me buy a plasma cutter for our 16 year anniversary. I started to buy a Chinese brand "ever

    last", but could not spend that much money without getting the best for a couple hundred more. I bought the hypertherm powermax 30. It works and cuts great, I am so glad I went with hypertherm.

    I read quite a bit on how to safely cut the tank and I spoke to my local propane company about how they cut them up. Take this as how I did it, not as advice on how to do it. (do not try this at home :). reading the net I filled and drained the tank twice. the first time I put Dawn soap the second time I put TSP and let it set for a few days until I was ready to cut. During this time I spoke to my local propane co. and asked how they cut them. He said they fill them with water and then as soon as they start to drain them, they make a cut at the top of the tank, with a torch. So I let a Little water out and cut the valve threads out. then I let a little more water out and cut a hole within the area of where I was going to cut for the fire box.

     I then drained the rest of the tank and then dragged it into my garage. I do not think I needed to, but I also stuck my leaf blower in the hole for a couple minutes, before my next cut. I measured the fire box and baffle plate to set about 4-5" below the cooking grate.

    I then flipped the tank over and cut the legs off the tank and ground them smooth. I then put a level on the fire box cut. Once I had it level, I chocked the tank with a couple 2x4's and marked out my doors. I may have messed up on the top cut putting it at almost 12 o'clock. I am still not sure if I am going to change this or not. I have read it is better to move the cut a couple inches off of 12 o'clock and I also read that on smaller tanks with smaller doors, if you put you cut closer to the top, it will keep rain from entering the smoker.

    This is as far as I got, within the couple hours i had to work on it. The next picture is just to show the cut with my plasma cutter. It is so nice compared to my torch and metal cutting saw.

    I need to make some hinges out of the legs I cut off the tank, before I finish cutting my doors.
  2. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Rod, morning.... Aren't plasma's the greatest thing since sliced bread ???   Good start on the build..  Dave
  3. boomhower

    boomhower Fire Starter


       Good start.  Plasma's are nice, I wish I had one. 

       Where's the build thread on the Jeep?   Are you on pirate?

  4. sqwib

    sqwib Smoking Guru OTBS Member

    Nice size, not too small and not too big, it's gonna be perfect!
  5. silenthunter

    silenthunter Fire Starter

    My willys build has been put on hold for a little bit, between buying, selling  our house, and work. Now that things are slowing down, I was going to get started on it again but wanted to build a smoker. The new plasma cutter will help out a bunch on my willys also. My daughter also made plans to get married in our back yard this next spring, which means the smoker will get a work out for the wedding.


    Heres a picture of my backyard, after I put in my flag pole.

  6. silenthunter

    silenthunter Fire Starter

    Thanks to boomhower for the diagram below. Does anyone have problems with water leaking into their smoker doors?


    Originally Posted by boomhower


    I cut the top at of the door at 10 degrees off of 12'oclock and the bottom of the door exactly at 3 o'clock. (So, my door is a total of 80 degrees of the tank circumference.

    Here's a section view of the smoker door:

    I hope this helps.....

  7. sqwib

    sqwib Smoking Guru OTBS Member

    Oh, so it's a Sub your building... sorry couldn't resist.

    Mine is under the deck I have an inner lip at the hinges and outside flat steel on sides and bottom, haven't had it in the rain yet so not sure if mine leaks or not.
  8. boomhower

    boomhower Fire Starter

    I know what you mean about putting projects on hold.  Marriage and kids did that to me...

    I went though your build thread.  Very nice.  I hadn't seen it before, but mostly because I'm never in the Willys forum.  I've been "working" on my TJ for years. (I go by IndyTJ on pirate)  I've got a '99 4.3 with a SM465 that I mated a flipped Dana300 to.  Hopefully, I'll get it put in one day and start wheelin again. 

    My  inspiration to build my smoker actually came from CJesse7's build thread that he posted over there.

  9. boomhower

    boomhower Fire Starter

        I wouldn't know.  I finished my smoker in April, and it hasn't rained here since.  (seriously).

    Although, I do have the stove seal around my smoker and firebox doors so I think that would limit rain getting in....

    Last edited: Jul 26, 2012
  10. silenthunter

    silenthunter Fire Starter

    I had a little bit of time to work on the smoker today.

    First I built some hinges out of the propane tank legs, that I cut off.

    Then I leveled the tank and made a jig out of two framing squares, zip ties, and a level. This would work with only one square, but with two it is hands free.  My original top cut was just off TDC.

    I decided I did not like the cut at 12 o'clock, so I welded it up and ground it smooth. I will come back later with a soft pad grinder to blend it all in.

    I am thinking of cutting a single door like a lang smoker. If anyone has any experience with a lang, please chime in. Like, how tall is the one piece door? Do you find the door too small? do you like the shelf type rack?
  11. silenthunter

    silenthunter Fire Starter

    I forgot to add that I think I am changing this to a trailer build. My buddy at work has an old 4x8 utility trailer with a broken frame. It has a good axle, springs, fenders, wheel/tires, and lights. I can not beat the price either, free for haul off. I think it is an old HF 4x8 trailer, but the axle should work fine and I will just build a new frame.. 
    Last edited: Jul 29, 2012
  12. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    Rodney, morning.... Don't you hate it when you change you mind on a build ????  

  13. silenthunter

    silenthunter Fire Starter

    I recut the top of my door at 3" below the original cut. I then drilled the hinges and set them at 8" in on each side. My door is 47" wide. heres a pic of how I lined them up.

    Once I had the tacked on , I welded the tank side solid. I also used a thick washer between the hinges with a 1/2" bolt.

    I welded a temp handle and door stop, and then I finished cuting the door. I had a hard time getting the door to open the first time due to the side cuts. The plasma cutter cuts such a fine line, and I had the torch angled just a little bit on the side cuts. This caused the cuts to be a little wider on the inside of the tank. Once I got the door open, I used the grinder to clean all the cuts and the door opens and closes great.

    I also picked up my free trailer from my friend. It has seen better days. But I hauled it home at 60 mph for 15 miles and the bearings stayed cool.

    It did not last very long.

    Thats all I could get done before my son got out of VBS  @ 1200hrs, and then it was family time. We went to pizza and the movies to see Ice Age.
  14. silenthunter

    silenthunter Fire Starter

    This was my 3rd partial day to work on my smoker. I got up and headed down to pick up the steel that I need. Which sucks because I live in the mountians,  and the steel shop is around 80 miles one way. I was able when I got home to build my trailer. I used 40' of 2x3x.188" to build it, with about a 3' piece left over that I will use to mount the tank.

    I cut 45* on the corners and then used a ratchet strap to hold everything tight while getting it square. Corner to corner was perfect.

    I made the trailer 4' x 6' and the tounge is out 3'9" for a total length of 9'9".

    I have c clamps holding the sping mounts currently. I need ti drill the holes and bolt it, on my next day off work. everything else is fully welded. The hitch and jack is from Harborfreight it is made by haul master and was like $45.

  15. scarbelly

    scarbelly Smoking Guru OTBS Member

    That is a great looking build. You do nice work 
  16. silenthunter

    silenthunter Fire Starter

    I am thinking of welding the fire box to the rear of my trailer. Is this a bad idea? or normal? I could use bolts to secure it. Or should I just let it free hang? I also thought about making the whole smoker bolt on to the trailer, but can not think of why I would need to ever take it off. it is probably best to just weld everything. any advice would help.

  17. daveomak

    daveomak Smoking Guru OTBS Member SMF Premier Member

    SH, afternoon.....   Think about building a skid for the smoker.... firebox attached to the smoking chamber of course....  Then it can be removed if need be.... attach with bolts to the trailer....  Then you can move it to a bigger trailer or move it to rearrange weight distribution...

    Just thinking out loud....   Dave
  18. boomhower

    boomhower Fire Starter


       Your build is looking good. 

    On mine, I debated the same thing.  I ended up spacing the firebox about an inch away from the frame of the trailer.  I then weld (2) pieces of 1/2" diameter rod between the firebox and the frame to support the firebox.  This will support the firebox yet won't transmit as much heat as a direct connection.   I didn't want all of the heat in the firebox being transmitted directly into the frame close to where the trailer spring shackles were.  The springs have rubber grommets in them and I didn't want those to get to hot.   You can also see I painted the back part of my frame by the firebox with the heat resistant paint.  The rest of the trailer is normal paint (hammered metal- light gray).


    liquidsteel likes this.
  19. silenthunter

    silenthunter Fire Starter

    I do like the idea of not having all the heat conduction to the frame. But I was afraid of that heavy of a box not being supported down low. I may use a couple connectors like you did, for support.

    I screwed up when I picked yp my steel. I got 1" instead of 1.5" flat for the door straps.

    Boom, What size did you do your fire box? have you had any heating issues?
  20. boomhower

    boomhower Fire Starter

    I used 3/16" x 2" for the door straps. FYI.  This gave me 3/4" overlap on the top of the doors, and left 1-1/4" for the stove gasket door seal to go on.  (I don't know if you're planning on using stove gasket or not)

    My firebox (I believe) is 22" x 22" x 24" tall.  As far as heating issues, I can get the smoker plenty hot, and I can control the temperature down to about 200 deg. F using a little charcoal.  The only "heating issues" I have is having to feed the firebox every 45 minutes to an hour.  If I were to do it again, I would probably use heavier plate for the firebox (I used 3/16") or build an insulated firebox.

    Keep it up man.  You're doing good. 


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