Flammenwerfer Assembly Continued

Greetings Me Droogs and Droogettes!

By my count, looks like at least two of y’all are building one of these things if the Zon referrals are right
Good on ya then!  So, in that, we continue:
OK Time to continue with the Weapon of Mass Destruction:  The Flammenwerfer
This part of the game, again the disclaimer:
Ok Nuff said.  If’n y’all ARE crazy enough to go through with this, you’ll be pleased.  Slightly Scorched but very well pleased with the results.  Today:  We’re gonna tackle the main Tank Prep, as in Prepping, drilling and tapping, then installing the bayonet valve that the hose will be attached to.  For this evolution, You’ll need the following part:
20 lb CO2 Tank https://amzn.to/2muHXH0
And the Tools to use:
Drill press with 1/2” chuck -or- (b) Power drill with 1/2″ chuck
1/2” drive socket wrench
9/16” 8-point socket 1/2” drive 
1/2” Dewalt pilot-point drill bit
37/64” Drill bit
3/8″-18 NPT thread tap
Cutting oil

Setup is as Follows.  At this point you’ve reattached the newly built Universal Filler Valve and tightened it down when performing your pressure/overpressure test.  With it set in the drill press (or workbench) measure out 90 degrees on either the left side or right side. 

Because the hose that feeds the fuel to the nozzle is only 3-4 foot long (I used a 3 foot hose) you need to insure that you cut in on the correct side of the tank.  If yer a righty, cut on the right side.  If’n yer a southpaw, cut left.  Once you unfuck yerself on the whole left/right thing, just realize that the pressure container, the 24oz CO2 Tank https://amzn.to/2moGdzl is going to be centered on the back of the tank on your frame.
Once you have the side picked out, Remove the Universal Tank Filler / Pressurization System.  Mark the side you want to use roughly one inch from the bottom.  Once you have the tank stripped down, roll it 90 degrees up to the side you wish to drill.  Measure ONE INCH from the base of the 20 lb CO2 Tank and https://amzn.to/2muHXH0  and then prep to drill. 
Make sure the tank is secure.  Squirt a lil cuttin’ oil on the spot your going to drill.  Using the 1/2” Dewalt pilot-point drill bit, begin cutting into the tank -SLOWLY AND CAREFULLY-.  You’ll be getting a huge amount of shavings and keep adding the cutting oil as needed.  Take your time and do it in stages is my approach.
This is your starting hole.  Once it’s cleanly punched through, change out to the larger finishing bit, the 37/64” Drill bit.  Add more cutting oil, and cleanly cut out the remaining metal, expanding the hole to 37/64ths.
OK.  So now you got the hole.  Take the square side of the 3/8″-18 NPT thread tap into the 9/16” 8-point socket 1/2” drive and insert the threaded side of the 3/8″-18 NPT thread tap into the 37/64” hole. Begin cutting the threads by turning the 3/8″-18 NPT thread tap clockwise ensuring that the 3/8″-18 NPT thread tap is perpendicular to the surface of the large tank.  
The is NO SUCH THING AS BEING TOO CAREFUL OR SLOW!   Make sure you cut slowly, adding cutting oil regularly so’s the thread cutter doesn’t get bonded or stuck to the metal. Continue cutting until only 6-7 threads of the 3/8″-18 NPT thread tap are exposed above the surface of the large tank.  This -should- complete this evolution.
Step Two: Rinse out the tank.
Now that you’ve drilled and tapped the tank, you HAVE to make sure you get ALL of the little fiddly bits of shavings and metal out of the tank.  Very carefully so as to not to damage the threads, use an old toothbrush or gun cleaning toothbrush to remove any clinging bits of aluminum around the tap hole.  Blow out / shake out all remaining bit.  Me?  I triple rinsed with water, shaking the shit out of the tank to make sure it was clean.  One itty-bit of metal in there when yer doing ‘flame on’ can cause BIG “Fiery-Ball-O’Death” Issues.  Big Safety Tip:  Thoroughly clean the tank.
Step Three:  Install the feeder nipple.
Parts Needed:
Male Quick Disconnect x 3/8” Male NPT https://amzn.to/2mPuxpg
20 lb CO2 Tank https://amzn.to/2muHXH0 (Now with hole drilled and tapped)
Yellow Teflon Tape
Tools Needed:
1/2” drive socket wrench
11/16” deep socket 1/2” drive
Take the Male Quick Disconnect x 3/8” Male NPT and wrap two to 2.5 times around the threads.  Mate up the threads to the 37/64” hole and thread it in.  Once you have it cleanly started, finish securing it completely to the tank using the socket wrench and 11/16 drive.

Annnnnnd more to go… we’re almost completed on the hard stuff…  the rest is pretty easy.  Lotsa pressure checks and a bit more modifications to the pressure washer wand, but for the most part, some of y’all cool kids make be able to figure out the rest…. Otherwise stay tuned and we’ll have ‘er dun by Friday of this coming week.
Until later, I Remain The Intrepid Reporter
Big Country

By BigCountryExpat

Fuck you if you can't take a joke. No one gets out alive so eat me.


  1. I've found some of the parts for this at my local TSC. Which is handy. I'm the inpatient type. Going slow ain't easy, but I'm trying.

  2. Wouldn't it have been safer to weld thread-olets into the tank rather than tapping and threading? Its more work and not as easy but you'd move any point of failure to the olet rather than the tank proper and it would re-enforce the connection so that rough handling wouldn't damage the connection.

    When working with pressurized gas cylinders there is no such thing as too careful. There is a calculation in industry that works out the blast area for a cylinder full of air that fails (ruptures), it gives you the tons of TNT equivalent.


  3. 1976 or so, I was in the parts department at the Chevrolet dealer in Sacramento.

    The shop crew were unloading oxy-acetylene cylinders (I suppose these were fresh fills from the welding supply shop).
    The 'rocket-scientists' — literally — moved the upright tanks onto the tailgate of a new pickup truck in preparation to lift them to the concrete floor.

    One tank nosed-over, smashing the valve into the concrete.

    At that point, everybody in six counties knew mischief was afoot.
    The HISS from the escaping gas was deafening a couple hundred feet away and inside another building.

    Propelled by the gas from the busted valve, the base of the tank blew through the cab of the pickup truck.
    And traveled across one side of the dealership shop… probably sixty feet.
    And blew through the concrete wall separating the two sides of the shop.
    And blew through the roof.
    And landed in the parking lot of the bank across the street.

    And yet, I routinely strap a 3,000psi SCUBA tank on my back.

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