Air Cannon Serves Up A Blast Of Ferrocerium Sparks

OK, looks like we have a new way to entertain the kids and wreak havoc in the neighborhood, if this spark-shooting ferrocerium cannon is as easy to build as it looks.

This one comes to us by well-known purveyor of eyebrow-singing projects [NightHawkInLight], whose propane torch never seems to get a break. The idea here is a large scale version of an apparently popular trick where the “flints” from lighters, which are actually rods of ferrocerium, an aptly named alloy of iron and cerium, are heated to a nearly molten state and dropped onto a hard surface. The molten alloy thence explodes in a shower of sparks, to the mirth and merriment of those in attendance.

[NightHawkInLight]’s version of the trick scales everything up. Rather than lighter flints, he uses ferrocerium rods from firestarters of the type used for camping. The rod is stuffed into a barrel formed from steel brake line which is connected to the output of a PVC air chamber. His ominpresent propane torch is attached in such a way as the flame plays upon the loaded pyrophoric plug, heating it to a molten state before the air is released from the chamber. The massive display of sparks seen in the video below is pretty impressive, but we’re getting tired of  gender reveal parties and forest fires.  We just hope he had fire extinguishers on hand.

Seriously, be careful with stuff like this. [NightHawkInLight] has a lot of experience working with these kinds of projects, from his plasma-propelled soda bottles to making synthetic rubies with an arc welder. We’re sure he wouldn’t want to see anyone get hurt.

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Fire Pit Burns To The Beat With Bluetooth

Humans have several primal fascinations and perhaps two of the biggest ones are fire and music. While you can picture some cavemen and cavewomen sitting around a fire beating on sticks for rhythm, we think they’d be impressed if the fire danced along with the music. Through the power of Bluetooth, that’s exactly what [Random Tech DIY’s] new fire pit does.

Technically, this is called a Rubens tube, and while it’s an old technology, the Bluetooth is a certainly a modern touch. As you might expect, most of this project is workshop time, cutting MDF and plastic. The audio system is off-the-shelf and drives some car stereo speakers. The results looked good, and although it always makes us nervous building things that carry propane gas, it seems to work well enough from where we’re sitting.

We had to wonder what things you could change that would affect the display. Changing the number of holes, the diameter of the holes, or the gas pressure, for example, would certainly change how the flames look and react to the sound waves.

We have seen other Rubens tube projects, of course. However, we were really interested in the use of these as crude oscilloscopes before the availability of cathode ray tubes. We’ve seen a modern take on that, too.

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BBQ Burners Built From Scratch

Building a barbecue is a common DIY pursuit, and one that comes with a tasty payoff at completion. While many projects focus on charcoal or wood-fired designs, [Andrew] is more of a gas man. Not one to simply buy off the shelf, he designed his own burners from scratch.

This quest wasn’t just unnecessary yak shaving; burners to suit [Andrew]’s desired size and power simply weren’t available. The burner is designed around the Venturi effect, wherein the propane gas is passed through a small orifice, creating a jet and pulling air along with it as it enters the burner tube. This causes the gases to mix, and they can then be ignited when passing through the outlet holes of the burner. Get the orifice and outlet holes sized just right, and you’ll have a burner that produces a hot, blue flame, perfect for efficient cooking.

The orifice was produced with brass plumbing components, and hooked up to a valve rated for use with gas lines. The burner tube itself was created from stainless steel tube, with slots cut to act as outlet holes and with the end crimped and welded shut. A black iron pipe reducer was then used as the air inlet and orifice mount.

The final result is a powerful barbecue burner that is perfectly sized to [Andrew]’s needs. If you’re keen to build your own custom rig, you may find this a useful and cheap way to go versus sourcing parts off the shelf. We’ve seen [Andrew]’s work before, too. Video after the break.

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Portable Pizza Oven Does The Job, And Fast

Pizza ovens are a fun thing to have in your back yard, and often wood is the fuel of choice for that smoky, rustic charm. However, [Andrew] is a fan of speed, leading him to prefer propane when it comes time to make a pizza. This guided his portable pizza oven build, with impressive results.

Hot, fresh pizza cooked in just minutes. Pretty attractive, huh?

With this build, [Andrew]’s goal was to have a portable oven that didn’t sacrifice on performance. Commercial offerings were easy to lug around, but tend to cool down too much after cooking a pie, leading to lengthy waits for the oven to return to temperature. Not content to wait, [Andrew] specified his build with two custom tube burners to heat the floor, with separate jet burners to heat the cavity. When two jets proved too much, he refined the design to just one to improve efficiency and reduce carbon build up.

The Instructable is a great read, covering both the design of the oven as well as the necessary techniques to cook high-quality Neapolitan pizzas in minutes flat – right down to the selection of flour and proper insertion techniques to avoid sticking. The home pizza enthusiast could learn a lot here, and it’s great to see [Andrew] continue to improve on his earlier designs. Video after the break.

This is only the most recent of many pizza ovens to grace these pages. How about one in a beer keg?

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Burning Propane Beautifully Illustrates How A Tesla Valve Works

When you hear the name “Tesla”, chances are good that thoughts turn instantly to the company that’s trying to reinvent the motor vehicle and every industry that makes it possible. While we applaud the effort, it’s a shame that they chose to appropriate the surname of a Serbian polymath as their corporate brand, because old [Nikola] did so many interesting things in his time, and deserves to be remembered in his own right.

Take the Tesla valve. In essence a diode for fluids, the Tesla valve uses a tortuous path to allow flow in one direction but severely restrict it in the other. Understanding how it works isn’t necessarily intuitive, though, which is why [NightHawkInLight] chose to demonstrate the Tesla valve principle with exploding propane. It’s not new territory to him; we’ve covered his propane-powered rifle in the past.

The swirling blue and green flame front in those experiments make burning propane the perfect working fluid to demonstrate how the Tesla valve works. The video below tells the tale, with high-speed footage showing the turbulence that restricts the reverse flow. The surprise discovery is that in the forward direction, the burning gas actually seems to accelerate as it moves down the valve; hypersonic Tesla plasma cannon, anyone?

We’ve seen Tesla valves before, including one made from a “Shrinky Dink”. That did a pretty good job of visualizing the flow patterns that make the valve work, but there’s a huge showmanship gap between tiny channels filled with colored water and the explosive decomposition of a fuel-air mix. It’s a bit riskier, and standard “don’t try this at home” disclaimers apply, but luckily [NightHawkInLight] still has his eyebrows, so he must be doing something right.

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Nerf Blaster Goes Next-level With Propane Power

There are no shortage of Nerf gun mods out there. From simply upgrading springs to removing air restrictors, the temptation of one-upping your opponents in a Nerf war speaks to many!

Not content with such lowly modifications [Peter Sripol] decided that his blaster needed to see some propane action.

[Peter] completely stripped out the existing firing mechanism before creating a new combustion chamber from some soldered copper pipe. He added a propane tank and valve on some 3D-printed mounts, and replaced the barrel to produce some intense firepower.

To ignite the fuel inside the combustion chamber, some taser circuitry creates the voltage needed to jump the spark gap inside whilst an added switch behind the trigger kicks off the whole process. After experimenting with different ignition methods, [Peter] eventually found that positioning the spark in the center of the chamber provided the best solution for efficient combustion and non-deafening volume.

Though highly dependant on the amount of gas in the chamber during combustion, the speed of the dart was able to reach a maximum of 220 fps – that’s a whopping 150mph!

Next follows the obligatory sequence for all souped-up Nerf guns:  slow motion annihilation of various food items and beverage containers. To obtain some extra punch, some custom Nerf darts were 3D-printed, including one with a fearsome nail spear-head.

We strongly advise against taking up [Peter] on any offer of Nerf based warfare, but you can check out his insane plane adventures or last winter’s air sled.

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Propane-Powered Plasma Rifle

It may not be a “phased plasma rifle in the 40-watt range,” and it doesn’t even use plasma in the strict definition, but it’s pretty cool nonetheless. It’s a propane-powered bottle-launching rifle, and it looks like a lot of fun.

[NighthawkInLight] sure likes things that go pop, like his watermelon-wasting air-powered cannon and cheesy-poof pop gun. This one has a little more oomph to it, powered as it is by a propane torch. The principle is simple: fill a soda bottle with propane, ignite the gas, fun ensues. The details are a little more subtle, though, and allowances need to be made to keep back pressure from preventing the projectile from filling with fuel. [NighthawkInLight] overcomes this with some clever machining of the barrel. The final production version in the video below is needlessly but delightfully complex, with a wooden stock and a coil of clear vinyl tubing helical plasma accumulator before the barrel; the last bit is just for show, and we have to admit that it looks pretty good.

Unless you count the pro tip on using CPVC pipe to make custom fittings, this one is nothing but fun. But we don’t have a problem with that.

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