Assemble a HHO Mini Torch From Plumbing Parts





Introduction: Assemble a HHO Mini Torch From Plumbing Parts

About: general bloke type of tinkering

Using plumbing parts, consisting of some compression and some solder fittings with the addition of a  ½"  L.P. gas hosetail, its possible to make a very servicable HHO gas torch.
The temps are very low and so solder fittings will work, they also serve to keep the weight down by reducing the number of heavy brass fittings needed.
My cell produces 1 lpm so the standard mig tip will need to be made smaller and we will cover that mod later on.

Step 1: Parts and Exploded View

The standard 15mm plumbing fittings are...
  1. 6 inches 15mm copper tube
    • 1" section between stopend and elbow.
    • 1 ¼ " section between the coupler and the ball valve.( length is 30mm but 32mm seats well)
    • remaining approx 4" between the elbow and ball valve.
  2. 15mm copper stopend.
  3. 15mm copper 90 ° elbow.
  4. coupler FIxC 15mm x ½ "
  5. ½ " BSP hosetail which is a standard LP gas fitting.
  6. mini ball valve compression fittings on both ends.
  7. mig welder tip either 0.8mm or 0.9mm which will be modified.
  8. a brass nut M6x1.9 for the mig tip.
The mig tip has a metric thread M6x1.0 mm, so you will need to drill and tap suitable material if you dont have a M6 brass nut at hand.

Step 2: The Torch Tip

The tip is the most fiddly part of construction due to the need for swapable tips. The copper stopend is too thin to support threading for the mig tip, so a brass nut is needed that can be soldered on in the inside, in order to remove the tip. I used the earth pin from a 15A 3pin plug which I drilled and tapped for M6 thread. Another option is the brass contacts on the old carbon dry cells which would also need to be drilled and tapped.

It’s easier to first drill and tap the copper stopend and brass nut seperately and then insert a SS bolt to line the parts up when soldering, this way the ss bolt can be easily removed afterwards once all the soldering is finished.

Don’t solder with the copper mig tip in place because you won’t be able to remove it again.

I had heard mig welder tips can be made smaller by tapping a ball bearing on top. It seems odd that forcing a ball bearing down would make the hole smaller, but the copper cant spread outwards and has nowhere else to go so it constricts thereby reducing the orifice diameter which works well.

The smallest mig tip is 0.6mm which was unobtainable, I have used both the 0.9mm and the 0.8mm and managed to get the hole size down to 0.45 mm which is the size of some stainless steel leader tooth proof fishing wire I use for replacing cheese slicer wire.

Step 3: Closing Bits

The body of these mini torches is usually filled with fine brass wool, which reduces the instances of flashback considerably, I have retained the insides from interferring in the ball valve with a bit of fine screen wrapped around a washer.
I used a M6 washer which I then had to grind down to fit inside the copper pipe.

Its very convenient to be able to shut off the gas at will without constant banging from flashbacks, however...

Don’t forget to switch off power to the cell once you have shut the ball valve, failure to do so will cause pressure buildup which could lead to leaks, explosions and equipment damage.



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    86 Discussions

    Your hho torch first you have to use Sodium Hydroxide second u should use a bubbler. You can shut off and not worry about built up pressure if u use a pressure senser in main voltage circuit, like everything else though have a bigger one i made 10 lpm

    1 reply

    If you saw my other gas related 'ibles, you'd know I use a bubbler and caustic soda(lye or sodium hydroxide).

    Pressure switch would be neat, but I dont want to put my trust in one considering the caustic environment.

    Can you use propane with this? If not can you rig it to make it work?

    1 reply

    No, propane generally needs metered air at the tip. If you can find a propane jet that will fit, it should work.

    I see the instructions for the tip but how about the tank for making the HHO? I know all it is is water with electric (DC) running thru it. but how do you do the plates and what is used for the tank?

    1 reply

    Depends on the availability of materials, I use 15mm thick perspex generally.

    Make a box and clamp the lid down.

    twin series plate cell.jpg

    2 years ago

    If you guys don't want orange flames, you need some sort of dessicant/filter to be in series with the gas hose. You need to remove the moisture from the gas, because that's the only way the sodium is being carried into the flame (it's dissolved in the microscopic water droplets that you can't see). A filter of calcium chloride (CaCl2) would be most effective, (but any common drying-agents should work), even activated charcoal may work. Just make sure it's not powdered, and that it's somewhat granulated; and if buying online, try to find products labeled "ANHYDROUS"; that is important if you want your drying agents to work like they should. Like sodium sulfate, which is a good drying agent normally, won't work if your using regular epsom salts, because epsom salt is hydrated sodium sulfate.

    Also I kinda just realized you can just avoid the orange flame entirely by not putting any sodium containing electrolytes in the solution. Just use potassium ones... like, go find some potassium carbonate, and call it a day.

    6 replies

    on most gas torches you are able to adjust the gas mix as the orange flame is caused by to little oxygen in the mix on twin gas torches like oxyacetylene you adjust each gas separately with the valves and on single gas torches you adjust the mix normally using a rotating collar that opens and closes the air allowed into the mix with this there does not seam to be any way to adjust the air fuel mix.

    Regards Poppy Ann.

    There is no air in this style of torch, the fuel and oxidizer are being created at the exact ratio thats required for combustion. For every 2 molecules of H2O being electrolyzed, there are created exactly two molecules of H2 (hydrogen gas) and one molecule of O2 (oxygen gas). A perfect ratio of combustion reactants will burn the hottest and most effecient with a blue flame, unless... your reactants are contaminated with water and sodium.

    Hi Nabzim,

    I know that a blue flame is the hottest you can get which is what you do when welding with either oxyacetylene or oxypropane but even though the perfect flame is achieved with a 2 to 1 mix fuel to oxidizer the mix also depends on where you are if you are in a very humid area then you will need a little more oxygen and in a very dry area you normally need a little less.

    In many years past friends and I use to build a set for home welding using a carbide lamp base which uses calcium carbide and water to produce acetylene and one of the medical oxygen cylinders both of which we could get from our local chemist the torch we made at work as they had all of the machine tools you could dream of and use in a lunch time was available, we even managed to use it to cut by heating the steel up to a orange colour then turning up the oxygen and then using the steel for a fuel whilst it was not the best way to cut it was the easiest way to mange at home as we were not allowed full size cylinders at a residential address.

    forgot to say last time, a great instructable many thanks for all your work.

    Regards Poppy Ann.

    Wait...I thought Epsom Salt is magnesium sulfate... Now I'm confused. \: l

    Although anhydrous magnesium sulfate would be a good drying agent as well... but its just too easy to buy some anhydrous calcium chloride.

    Im so sorry, you are totally correct!

    I realize this is old but was hoping to maybe get some input. I once read that you could reduce the hole on the torch tip small enough to allow the gas to flow but actually be to small for the flame to pass through. This doesn't mean you shouldn't still use a flashback or at the very least some sort of bubbler but is yet a major additional safety feature.

    I'm working with a company that has the capability of actually creating tubing in any inside and outside diameter I wish and was going to do some experimenting. It's not exactly cheap so I'm trying to accumulate all the info and advice I can in this regard. I currently have a small sample that you need a maganfying glass to even see there's a hole. They can't go much smaller than this but I actually think it's to small. I didn't write down the actual hole size for the sample they gave me.

    So, can anyone here tell me the smallest size hole I can go fo mixed HHO like in this setup? If you happen to know the smallest size I can go for each of the gasses separately I'd appreciate that as well! Thanks!!

    2 replies

    I read an ible a few days ago that was using a hypodermic needle for the tip. It also seemed to me that an "Ink Cartridge refilling" plastic bottle and stainless tube might be ok. What about the brass "needle" that is used for filling air into "soccer" balls ?

    The Smith Little Torch used by jewelers has several tips that have drilled rubies in them for very durable very small tip orifices - used for Propane/Oxygen set ups.

    Why not just use an oxy/acetylene welding tip instead of a mig tip?

    1 reply

    You mean something like a brazing tip?


    2 years ago

    perhaps use a needle valve which is superior to finely control volume accessable close to the handle. then further but still close use a ball valve for quick shut off.

    If you don't use some sort of dryer the flame will be yellow, there are examples of diy dryers on the internet. The more you filter the hho the clearer it gets.