If you're anything like me, you probably loved the show "Stranger Things". But I didn't just like it because of the actors..... In fact, I thought Stranger Things was one of the better Netflix shows based on it's production, filming, and prop(s). In particular, the flamethrower was sick!
That's why I wanted to build one and not only make something that looked cool, but also worked as it should.
It started out as a thought. How could I build one just like it? I had two pictures, that's all.
These two pictures would pave the way for the design, build, and performance of the flame thrower. It had to look real, be mobile, and shoot flame as far as possible
In the first picture, we can get ample information. First and most obvious, there are 4 torch tips. From the side, each looks as though it's just pointed inward on one plain, but it actually makes a bit of an X so they must be pointed to the center of their diameter. This X torch concept created an intense ignition point for the liquid fuel that passes through it.
We can also see two silver tubes on either side of the door frame. Hmmm... where does this look familiar from?? Maybe some 3inch PCV tube??? It's pretty funny when you start to realized just what the original creators had to do to spiff up some off the shelf flame thrower!
If we estimate the silver tubes on the back of the guy in the above picture to be ~3inches in diameter, it gives us a good baseline for the rest of the dimensions. The tip of the gun (all four torches) looks to be close to about 4 inches in diameter. Thus, a 2inch center barrel, and one inch torch barrels gives us just that
1(2)1 = 4
This picture is from Day 1. yes that's my bed, and yes I slept with it that night. It just looks so awesome right????
I used all raw material to start with. The center tube and torch tubes are aluminum 6160. Cut on a lathe and machined in a mill give the unique barrel look to the center tube. The center tube is just a show piece to cover the propane lines going to the torches and the tube that the flammable mixture flows through.
Each torch tip was a bit of a process. It turns out, torch design is actually quite complicated! In order to have a successful torch (by successful I mean nice blue tip flame) you have to have two things correct; The air and fuel mixture, and the mixing tube length. The latter, not too critical. The former, mixing air and fuel just right... a total pain!
How does one mix air and fuel? With something called a venturi! Ventruis work by accelerating one fluid, which creates a lower pressure that atmosphere, and thus another fluid (air) rushes in to equalize the pressure differential. I wont get into the specifics, but needless to say there's a bit of math and trial and error to getting it right. Not enough air and you get a floppy yellow flame. Too much air, and it wont stay lit!
Here you can see it starting to come together. I used a pressure washer handle purchased from Amazon and if you're wondering where the yellow tank came from, it's a used scuba tank I found on craigslist! At the bottom of the tank I drilled and tapped a 3/8 NPT fitting. The top of the tank is sporting a custom made 4041 stainless steel valve which goes to a paintball CO2 tank. The CO2 tank pressurizes the fuel mixture and forces it out the pressure washer handle at ~3,000 PSI.
Once the base concept was together, I did a quick test to confirm it worked.
From here, all that was left was to design and add a shoulder stock, tubes to match the show's silver tubes, and then paint!
And this is what she looked like before the paint and shoulder stock! Yep, that's right, I didn't used the standard homedepot 3inch PVC.... Two reasons (1) my paintball tank wouldn't fit into the 3inch PVC (it was being used to hide both the propane and CO2 tanks) and (2) PVC is expensive! well... not that expensive. But end caps plus the material would have set me back $20 and I was trying to keep this build as low as possible. Turns out my friend had some old gas line markers that his company recycles when they are faded and they fit perfectly!
After that, I machined some more aluminum for the shoulder stock and painted it all black to match the show. In my honest opinion though, it looked so much better in all silver.
I really enjoyed this build and surprisingly learned so much! Check out the video below to see it in action! Cheers!
The concept of throwing fire as a weapon has existed since ancient times. Early flame weapons date from the Byzantine era, whose inhabitants used rudimentary hand-pumped flamethrowers on board their naval ships in the early 1st century AD (see Greek fire). Greek fire, extensively used by the Byzantine Empire, is said to have been invented by Kallinikos (Callinicus) of Heliopolis, probably about 673. The flamethrower found its origins also in the Byzantine Empire, employing Greek fire in a device of a hand-held pump that shot bursts of Greek fire via a siphon-hose and piston, igniting it with a match, similar to modern versions, as it was ejected. Greek fire, used primarily at sea, gave the Byzantines a substantial military advantage against enemies such as members of the Arab Empire (who later adopted the use of Greek fire). An 11th-century illustration of its use survives in the John Skylitzes manuscript.