HHO Generator Makes Bubbles That Go Boom

Here’s [Phil] showing off the components he used to make an HHO generator. The device uses household items to generate hydrogen and oxygen from water using electrolysis.

He’s using a plastic Nesquik container as the vessel for his experiment. Inside is water doped with a bit of baking soda. The lid plays host to the majority of components. There are electrodes which stick through the lid of the container. To help boost the productivity of the generator these electrodes have several metal washers suspended between. It’s importnat to avoid a short circuit so they’re mounted with the plastic bolt from a toilet seat, and isolated using hot glue. A plastic tube used collects the gasses. You can tweak the ratio of what’s being collected by reversing the polarity of the battery.

It’s interesting to see soap bubbles lit on fire in the demo video. But there are more serious uses for this concept. People have been working on making it feasible to power cars from the hydrogen generated this way. We’ve also seen a plastic bottle rocket powered from an HHO generator, and there’s always the thought of building your own miniature dirigible.


67 thoughts on “HHO Generator Makes Bubbles That Go Boom

  1. Can we please try to stay away from “fringe science.” Electrolysis produces oxyhyrogen: a stoicheometric blend of two diatomic gases (Oxygen and Hydrogen)… NOT some impossible thermodynamically unstable conformation of Hydrogen and Oxygen (HHO) which has yet to be proven by ANY laboratory in the world!

      1. But! but! but!

        People have proven that they get more power from converting water to HHO and running the car on that than running the car on the electricity directly!… or at least that’s what they claim… :P

        But no, producing oxygen and hydrogen on the go isn’t energy efficient, storing the mixed gas is dangerous and we are already making cars that use pure hydrogen as fuel so i don’t really understand the hype about trying to do it over again.

        1. Yes there are loss, but there is a possible mechanism by which a HHO generator could make for a overall efficiency of a car. Petrol cars don’t operate on a perfect otto cycle, In the theoretical otto cycle the the pressure rise on ignition is instant. In reality there’s always some delay as the flame spreads away from the spark plug(it’s a deflaguration rather than a detonation), and that slower flame means a slower rise in pressure and lower peak pressure, and lower power per unit of fuel burnt. Speed up combustion say by adding oxy hydrogen as a kind of accelerant and I’m sure that the flame front will travel faster igniting the fuel faster, raising pressure faster, and causing a higher peak pressure and a thermodynamically more perfect otto cycle. Should be said there is significantly more chance of blowing the engine up.

    1. Aren’t you overreacting a bit? I always thought HHO was just a simple way of expressing two parts hydrogen and one part oxygen, though not as a single molecule. It’s still H2 and O2 that are forming in there.

      I have also heard HHO used as a sarcastic/joking description of water, like DHMO does, but I have to say “obvious joke is obvious”.

    2. Interesting, but I am pretty sure that I first tried this in grade 7 with a model train transformer and a garbage bag. Nice fireball if I remember, but boy did I get that science teacher in trouble ;)

      Later on, I found using a steel mesh for the cathode/anode works best, palladium works too. grin

      1. Steel not so much, it dissolves/oxidizes & makes the water filthy. You want something inert like palladium… or carbon. Carbon rods (pencil, CZn battery cores) are easier to use.. maybe carbon fiber (mesh) for more surface area.

        Yeah I did this too when I was a little kid, but I isolated the two sides in inverted test tubes not because I knew there would be two different elements but I liked seeing the “science-y bubbles” in two places.

    3. The stoichiometric air:fuel ratio for hydrogen 34:1 (by mass) or 2.39:1 (by volume) not 2:1. The heat of the hydrogen combustion with oxygen in the air heats the other gasses (mostly nitrogen) causing them to expand and exert force on pistons, turbine blades etc.

      Gasoline and any other fuel works the same way. If only the amount of oxygen in the air was admitted to any sort of combustion engine, it wouldn’t work. All the non-oxygen gasses must be present as a ‘working fluid’ for the combustion process to heat up and cause to expand. The combustion products of the fuel are the least part of what produces the force to run an engine or propel a jet turbine.

      By volume, dry air contains 78.09% nitrogen, 20.95% oxygen, 0.93% argon, 0.039% carbon dioxide, and small amounts of other gases. Air also contains a variable amount of water vapor, on average around 1%.

      A pure mix of 2 parts oxygen and 1 part hydrogen in a closed container won’t explode the container when ignited. A mix of 34 parts air and 1 part hydrogen will make a very loud kaboom – because the heat causes the gasses not taking part in the combustion to expand rather violently.

      Most of the propulsive force used in combustion engines is from the nitrogen heated by the fuel combustion with the oxygen.

      So if you’re fiddling around with running electricity through water, keep all sparks and open flames far away.

      1. “A pure mix of 2 parts oxygen and 1 part hydrogen in a closed container won’t explode the container when ignited.”

        I’m pretty sure it will.

        You’re forgetting that the resulting water gas is heated up by the combustion and expands just the same. Burning oxyhydrogen doesn’t “implode” like some people seem to believe.

        1. It will expand first, then implode, if you were to fill a sealed soda can with oxygen and hydrogen and ignite it, unless it ruptured from the initial expansion it would implode.

          However i have seen some quite spectacular explosions made using only oxygen and hydrogen so it definitely expands (explodes) before contracting (imploding).

          1. Sven… time for you to go back to school… If the volume if full with the correct mixture of H2 and O2, you’ll get an enormous detonation, only acethylene would be faster… The steam released by the detonation will expand about 1000 times more then Nitrogen could, the more H2 the more steam to be released…
            Please go study some more books…

  2. I fail to see how this is pseudoscience or “fringe science”. It’s basic electrolysis of water to separate it into it’s constituents of hydrogen and oxygen. Sure, it’s not “HHO”, and both hydrogen and oxygen gases are primarily stable in a diatomic molecular form, but it seems that your only problem is with the name.

    Okay, fine, shouldn’t call it HHO, but it IS science.


    1. Because they take a well established reaction and try to make it into something that it’s not.There’s nothing pseudoscientific about the electrolysis process itself, but what these guys are doing with it, or what they think they’re doing with it.

      The whole deal about the “HHO” gas, and people who call it HHO is the water car fantasy where you take an electrolysis cell, power it by the car’s alternator and feed the gasses back into the engine that turns the alternator – to run your car on water, or if that sounds too incredible, at least save some fuel due to some voodoo. It’s the same tier with fuel line magnets or pouring a cup of acetone in your gas tank.

      It’s really the HaD writers who dip their toes into pseudoscience by implying it might be “feasible to power cars from the hydrogen generated this way”.

      1. The whole deal of the “water car” is a misunderstanding, I think. It came about right around the time of WWII, I believe. There was a lot of fuel rationing going on at the time, so as a work around, many people converted their vehicle to run on “wood gas”. This is basically Carbon Monoxide, H2, and water vapor. This was normally done using pyroyisis on wood chips. I suspect that someone figured out that they could take a carbon arc light/torch, and by placing it under water, generate carbon monoxide much easier, on demand, instead of in large batches that once started were difficult to halt and restart. So I guess there really was a “water engine”, but the real fuel was the carbon rods that they burned up!

      1. I in now way meant to put down the video… I was actually disappointed in Hack-a-day for perpetuating the misnomer of HHO. Everything else is fine. Just another average fun day of lighting hydrogen and oxygen on fire! 8^)

  3. Not entirely related but I seem to remember if you’re looking to generate hydrogen alone then performing electrolysis on urine requires something like 4x lower voltage and by extension power. I forget what’s produced at the other electrode and more importantly whether it’d gum it up.

    1. my son did one with urine for a science fair and it was pretty gruesome. Less voltage was required. Faster production, fun flames, bad piss smell, horrified judges, basically all the standard stuff. The electrodes were 3/4″ fitting brushes and the thing produced waay more scale than just water and baking soda or whatever. a urine based system would require much more maintanence than you might be prepared to need to do

  4. For anybody wishing to research HHO using Google, it is commonly called “Brown’s Gas”. It can be dangerous if stored for later use and should be generated on demand. Fuel-air explosive such as this are some of the most powerful devices available.

    1. Powerfull? No, it’s a gas, so you can’t really have a lot of it in one place, the solids will easily beat it…

      However, hydrogen (unlike flammable hydrocarbons) has a very wide fuel-air ratio where it will burn and apart the extremes, it will easily go from deflagration to detonation, with accompanying destructive effects, that is the only real danger from this (apart the obvious playing with fire :D )

      1. Fuel air explosives have a greater pressure effect despite their lower energy density, because they’re by their very nature more dispersed. Instead of a sharp shockwave, they move a lot of air very violently and knock down and throw things around much more than high explosives.

        It’s like the difference between being shot with a bullet, and being rammed by a truck. The bullet may go through steel, but the truck knocks down a wall.

      1. Yes.
        It’s called a Hoffman voltameter, an old device for recording how much DC current had passed via the mass transferred between electrodes, or in gas produced at electrodes the gas collects in tubes above electrode. (Faraday’s constant and all that). Pretty easy to produce pressurised gas too. just pressurise the water!
        Problem with a Hoffman voltameter is the current path though the liquid is pretty long so the “water” adds a lot of resistance into the circuit, and turns it in an electric water heater that’s using the water as a heating element (P=I^2 *R). That adds inefficiencies and ups the voltage required to get a decent current going.

        For a short path allowing low voltages you really need a barrier between the electrodes which is permeable to ions, but impermeable to gases. Something like Nafion might be part of a solution, but I’ve never found a place that’ll sell it/expect it’s too pricey for me to experiment with.

        I’ve successfully make a fairly conventional type Hoffman voltameter with an extra short path for the current to take. use 2^n n>1 , tubular electrodes each of which have a plain enamelled wire for electrical power. fed wire through a hole in the wall of a length of silicone tubing, and the tubular electrodes pulled up inside the tubing so it ends up recessed by a few mm. Seal hole for wire. As gas bubbles hopefully want to rise in liquid, that recess forms a simple one-way trap for any gas liberated at the electrode ( like an inverted form of the U-bend for a loo). glue a batch of electrodes together, and wire up and plumb together alternating pairs of electrodes, and feed on DC. It does work, but as the electrical path length through the water and the effective plate area is so much less than for a plate electrolysis, you need a lot more voltage(inefficient) to get even a half decent gas production rate. Would probably work better with square section tube to minimise the space between tubing. but the most important thing for efficiency seems to be getting the current path length through the water down!

  5. Everyone knows this doesn’t work.
    Mythbusters couldn’t even make a bubble, therefore this man is using baking soda and vinegar.

    Oh wait? What’s that you say? They lied about the whole thing?
    Their are police stations that use small “HHO” jars to get more mileage?
    Bob lazaar uses a windmill/solar setup to produce his “HHO” that runs his camero?

    Fairy tales. Fairy tales everywhere.

    1. You are an idiot. Do us all a favor a google “electrolysis” to see the science behind these fairy tales.

      Of course you don’t get more energy out than you put in, but it is real. I have made a much bigger electrolysis rig myself.

      1. I would advice you to actually read what people write before calling them idiots, look at that last line where he says “fairy tales”, he is quoting common opinions that deny the science that says this doesn’t work, people who believe in lies dressed up as science often resort to making up enormous world-wide cover ups that would explain why their version of the laws of nature aren’t known to the general public.

        1. Compare the indicator diagrams of a *real* otto cycle engine to an *theoretical* otto cycle engine’s and you’ll maybe see how it can produce more power. A small amount of HH0 will speed up combustion and speeding up combustion move a real otto engine closer to the theoretical ideal by improving the combustion. Yes there’s are energy costs to making HH0, but say it absorbs 1HP of power, If spending that 1HP improves combustion by more than 1HP it’s a net gain in output. it’s not “free energy” from nothing, but energy that would otherwise end up in the exhaust.

          As to HHO generators I’ve made one myself out of lengths of 10mm square bar arranged on a 6 by 6 grid pattern, with 2mm of plastic spacers between the bars. electrical connection by “eye” over threaded bar screwed axially into end of bars. polarity of each bar alternated, so those “inside” the pattern were working on all 4 sides, boosting effective surface area. Combined with thin gap the lower resistance to overcome works out at higher current/efficiency. Resistance of device when filled with plain local tap water worked out at about an ohm, so I assumed it would be fine to use my modified computer PSU as a high current source. on 5V it fizzed off quite a lot of HH0 (and steam it should be said P=I^2*R) for a few seconds and then it all cut out. Checked the car fuse I’d used to try to implement overcurrent protection and while it hadn’t blown it had melted it’s plastic body. put a current meter in circuit, and tried again after power supply had cooled down. Current draw was over the 10Amp the meter could cope with, blowing it, and psu gave out the magic smoke for the last time. Suggests that the resistance of water drops once electrolysis gets going.

  6. Hydrogen/Oxygen mix is an extremely power explosive. The amount he can make just using the equipment on the picture is enough to make some serious bodily harm. There absolutely has to be some water safety valve in this picture somewhere, and I don’t see it.

    When I was much younger than the dude in that picture, I played with electrolysis of water. Taught me two things: never use uninsulated tools (a different story) and don’t mess with Hydroxy mix. If you provide enough positive pressure, It does burn insanely hot, and melting some metal with it was fun. But if the positive pressure goes away, there’s nothing stopping the flame from getting back into your storage – both fuel and oxidizer are there and there’s nothing stopping the explosion if there’s no safety valve somewhere very close to the output of your generator.

    My own humble experience has been – instead of extinguishing the flame by clamping the tubing close to the opening, I turned power off. Pressure started dropping and the flame happily went all the way back to the storage (same plastic bottle – type that he has here only with bottom cut off and floating in water) and – BOOM. The room was a mess, the installation was destroyed and I lost use of my right hand for a good part of an hour because the plastic bottle cap stroke in on its way out. If that was an eye, it would be lost for good. If there was any rigid of metal part in that installation, if would have been much worse.

    So, don’t mess with hydroxy mix!!!

  7. Obligatory safety notice, Hydrogen Oxygen stochiometric mixes are incredibly dangerous. It doesn’t take much to set it off, and when it goes it REALLY goes!

    My personal experience involved being a teenager, and wondering whether there was any electrolyte left inside a car battery I had been charging overnight, plus one lit match. Possibly one of the stupidest things I’ve ever done, but fortunately it only blew the top off the battery (I had all the caps open so it was probably safer than it could have been).

    Its probably safer to ensure there are separate capturing vessels for the hydrogen and oxygen, and pipe them both separately to your application (such as a fuel cell or something).

    1. Bofors (large Swedish weapons industry company) made a lot of safety videos in the 80’s, this sounds a lot like one of them. The videos usually consisted of several examples of how to do something dangerous and then a few tips on how to avoid it. They did several incrementally worse examples of oxygen/hydrogen in car batteries where the worst case scenario was a battery charged over night with a low liquid level and then lit by a spark (such as connecting a wire to the battery). The battery exploded completely spewing acid and sharp plastic pieces everywhere.

  8. Has anyone of the Hackaday attendees tried to use electrolysis in order to produce NaOH solution for PCB developer from NaCl solution? I don’t say that it is cheaper than using a commercial product but it might be an easier solution in case that someone doesn’t have an easy access to commercial products.

    1. Safer to source dishwasher powder, which is largely NaOH. Electrolysis of NaCl solution will evolve a mixture of hydrogen, oxygen and chlorine, and if you’re unlucky you might end up with some sodium chlorate by the end (which is a pretty powerful oxidiser on its own, known to be explosive).

      The biggest issue would be the cost and time. You’d need some electrodes that wouldn’t break down and be eroded, and a good way of getting rid of the extra hydrogen and chlorine. These two are photoreactive, so if you ended up with a buildup of the two and shone a bright light on it, BOOM!

  9. I did some experiments of this sort. What I got out of it could have been far more than singed eyebrows had I used a higher pressure vessel/container… Id recommend thin plastic and a bubbler to trap flashback as the stuff is in a very good ratio to burn, In fact no way I’d light a match next to a liter of the stuff

  10. Someone seems to be missing the bigger picture, Yes he is producing Hydrogen and it goes POP. but he is using electrolysis in a solution of Baking Soda and Water. I’m pretty sure there are other gasses going to be created by this process and allthough you are able to burn off the H I suspect these are not going to brake down. I would be interested to see what our chemistry experts have to say about that.
    Also the water in the tank will be contaminated after the process, you will end up with a pretty nasty solution and one that Is likely to just end up being flushed down the sink.

    1. Baking soda is NaHCO3 there just to provide ions to conduct electons. You could use just about any salt for this purpose, or obscenely high currents. Unless you’re generating hydrogen this way on a truly industrial scale there’s little to affect the process. You’re not going to get appreciable amounts of anything other than H2 and O2 from this reaction, which when combusted turn back into water. You might get some chlorine if you use tap water and are close to your municipality’s treatment center but nothing in your water will really change what’s going on in this already inefficient process.

  11. I was just thinking you could make a tiny one of these onto a depleted co2 canister with a replaced valve (or something) and have a water fuelled air gun using a real explosive.
    I know that sounds dangerous as fuck but this isn’t Health’n’Safety-A-Day!!

  12. 1. Don’t make videos sitting on the floor. Try using a Table.
    2.Move the equipment closer to the camera, makes it easier to see.
    3. When exploding bubbles, don’t hold the glass. WE CAN’T SEE – and you could lose a finger in big explosions. “I had fulminate of mercury in my right hand, now they call me Leftie”

  13. Guys, I follow you since… UHM, YEARS? Please, come on… this is just BS, that’s not HHO it’s simply 2h o2, btw, what tha fuck, you picked up the only video in youtube where a guy don’t even have a fucking chair and a table?
    Please, respect the audience, this blog is supposed to be read by smart people not “by dummies”.
    Are you trying to let fail in the dungeon this site? One of your blogger left, now you want to sell the site… Please don’t let this blog die…

  14. HHO is not speudo science. Though clearly overunity-claims and “fuelsaving”claims with HHO is.
    Actually I use a microtorch powered by an HHO generator almost daily.
    I use this to do microwelds (hardsolder/silversolder).
    This is a legitimate use of an HHO generator (I use one simular to the jewelry version of an aquaflame) .
    Yes it uses more energy than the caloric output of the HHO can ever be.
    But it’s a great way to do tiny brazing and flame polishing.
    Other bonus is that we only have to fill the generator with (demi)water once in a while.
    (not having to buy expensive oxygen gas-bottles and butane/propane-gas bottles makes it economically viable anyways).

    1. unless by tweak, ya mean which gas’s produced on which side. seein as that IS polarity-dependant. switchin the polarity kin control that.

      yes its dangerous, an’ a good way t’ make a bomb, but done right ya kin end up with a cost-effective torch fer light stuff.

      1. Yeah. But it doesn’t work until you’ve replaced most of the air (nitrogen) in the box. By that time you get the 2H2 + O2 mix out of the tube the ratio will be the right one.

        His first “woof” combustion still had too much nitrogen mixed into the bubble so that it couldn’t explode.

        To increase production, anything above 3V should do, but increase the surface area of the plates.

  15. The viability of HHO generators is closely related to the cost of Gasoline.

    as gasoline cost increases, the viability of using a supplemental fuel generator increases.

    so long as you can find a way to produce greater power than the generator requires to produce the gas.

    I see a net loss in power over the long term. Show me an engine that actually gets better gas mileage or produces more power than one running strictly on gasoline, and do it with an alternator and no battery.

  16. the amount of electricity required to produce enough oxyhydrogen to power a small engine produces more KINETIC energy than the electricity would alone, simply because our gas powered engines and rocket engines are more efficient than out electric motors. i made a small boat that had a dixie cup and a nine volt battery on it, the gas went through to a pulsejet and a turboprop style propeller in the water. it is more efficient, you don’t get more energy, you get more work. go back to highschool physics guys. and sorry i don’t have a video, i’ll go towards rebuilding it and putting it up soon.

  17. The reason that it makes cars more fuel efficient is because petrol only burns as a vapor, not as a liquid. In the combustion chamber, on 15-25% of the petrol vaporizes and burns and the rest will then vaporize, AFTER combustion and just go right out the tail pipe. By introducing hydrogen into the combustion chamber, more petrol will vaporize before the combustion process ends, which means better efficiency and lower emmisions

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