FAQ- Hydrogen Brazing Machine


1.No Flashback ? How is that possible ?

Yes, Safeflame unit will not get flashback from their flame and torch. It is not magic. Safeflame was the result of an EU funded project to research for a "safer flame" without using compressed gas bottles, chemicals and/or alcohols.


Traditionally all flames from Propane, Acetylene, Natural Gas, HHO fuel gases are "pre-mix" flames ie the Fuel gas is mixed with oxygen before it reaches the torch tip for combustion. These flames are very prone to "Lightback" or "Flashback". Too much gas, the flame will try to lift off, too little gas the flame will try to travel in the opposite direction into the torch.


Flashback can and will occur because it is a "pre-mix" gas system. Hence for those applications there is a requirement to install flashback arrestors (Fba) in the gas hoses / torches for safety reasons.


These Fba's have to be certified for the appropriate fuel gases. There will be Fba for propane, acetylene, hydrogen etc. We are not aware of any Fba's that are certified for HHO fuel gas over 0.5 bar that is available in the market and therefore care should be taken to ensure that the correct certified Fba's are used by whatever system that you choose to use.


Some of those HHO suppliers are claiming that they use Fba's that are tested to safety standards, in particular ISO 5175 and EN 730. However these standards specifically excludes Oxy-Hydrogen systems or HHO. That is a blatant mis-representation of facts. The responsibilty for the use of those machines to make sure they are safe and "fit for purpose" lies with you. So care should be taken in choosing your "Gas from water system".


Stoichiometric HHO gas mixture is the worst mixture for flashback to occur. For a lot of HHO systems in the market today, they use a few Flashback arrestors in series to try to overcome this problem.


For Safeflame unit with the specially designed "post-mix" torch (i.e the gases are only mixed at the tip of the torch), Fba is not necessary and flashback is not possible. Why ? Because the fuel gas, hydrogen is only mixed with oxygen at the tip of the torch nozzle and on the outside. When there is too little gas or too large a torch nozzle tip, the flame will try to travel back to the inside of the torch. It will not produce a flashback because when the flame tries to go back into the hydrogen gas line which has 100% pure hydrogen, it won't combust. If the flame tries to go back into the 100% pure oxygen gas line, it will be the same because oxygen on it's own won't combust. Hence Flashback is not possible.


Another side benefit of the "post-mix" torch is that the torch nozzle is very tolerant and frequent change of nozzle tip to match the flame size is not necessary. Of course if the post-mix gas is too much it will eventually lift off but usually at reasonably high gas output. Hydrogen is a very diffusable gas and so is the perfect gas for post-mix flame.

2.There is no mention of how to setup your Safeflame unit for use. In some HHO systems there are Youtube videos showing how to prepare and get the system ready for use.

To set up a Safeflame unit ready for use, it is very simple. This is detailed in the User Manual that comes with each Safeflame unit we supply. You don't even have to wear safety glasses because we only use water, no chemicals at all. Next, plug the power supply to the back of the unit. Then connect the gas outlets to the torch gas hoses which have right hand and left hand fittings to avoid any chance of a mistake. That's it. Turn the machine on/off switch in the front and light the specially designed post-mix torch. That will take about 3-5 minutes.

3.Why do you quote your Safeflame unit output in LPM whereas most other HHO systems quote in LPH ?

Safeflame unit produces separate streams of Hydrogen and Oxygen gases by electrolysis from PEM Electrolysers. When we quote our machine output, let's say 4 LPM (litres per minute), it is indicating that it will output 4 LPM of hydrogen gas and 2 LPM of Oxygen gas as water is made up of H2O ie 2 parts Hydrogen and 1 part Oxygen. The total combined gas output is actually 6 LPM. Most HHO systems which usually quote in LPH (litres per hour) of combined gases (because the gases produced are already mixed HHO and so they cannot quote separate gas output) making the gas output figures look a bit bigger and appear more impressive.


In order to make a true comparison between a Safeflame unit (LPM of Hydrogen gas only) with a HHO unit (LPH of combined H2 and O2 gases), one has to work out the Safeflame "equivalent" gas output. In the above example for a same size machine, the HHO system will quote their machine output as 360 LPH (4+2=6LPMx60mins=360). In addition most HHO systems don't recommend their users to use their machine at full capacity.


In fact in some cases. they are recommended to use them at no more than 50% capacity !!!. So make sure you make the correct comparison before making your decision.

4.Can Safeflame unit work above ground level ?

Safeflame unit produces separate streams of Hydrogen and Oxygen gases by electrolysis from PEM Electrolysers. Hydrogen being lighter than air can rise easily up the gas hose. Similarly oxygen gas travels up the gas hose from the electrolyser. There is hardly any registable pressure increase for up to 5m vertically. In addition, for the Safeflame unit there is a facility near the torch end for the remote "On/Off" and "boost button". Visit the "Gallery" tab on this website to see the test done on using the Safeflame unit 5m above the Safeflame unit.

5.For Oxy-propane / Oxy-Acetylene, the hottest part of the flame is at the tip of the inner cone, where's the hottest point of the flame for Safeflame?

Traditional Oxy-propane / Oxy-Acetylene, the hottest part of the flame is at the tip of the inner cone. Safeflame produces a pure hydrogen flame and it is soft and hot (~2700C). Due to the high diffusivity of hydrogen (which comes out of the torch in the centre ), it is mixed with oxygen outside the torch and so it does not have an inner cone. The temperature of the flame is evenly distributed and about 2700C. Hence it is much easier for brazing pipes.

6.How does the cost of owning and running Safeflame compared to Gas bottles and Oxy-Acetylene gas / torch?

The Safeflame units are a bit more expensive to start off with. Once the unit is purchased, the on-going costs are de-ionised / distilled water and occasional water filter and Silica Drying pellets to replace. The capital cost of the Safeflame unit can be depreciated over the lifetime of the unit, typically 10 years or more.


For Oxy-Acetylene system, one has to pay rental on the Oxygen and Hydrogen gases. Then there is the cost of the Oxygen and Acetylene gas itself. In addition in-direct costs like running out of gases and spending time getting replacement gas bottles, transport costs etc. If a brazing piece using Oxy-Acetylene is damaged because of the high flame intensity, time taken to remove and re-do takes time etc.


Over a 5 year period, comparison of Safeflame v Oxy-Acetylene gas system, that come out to be more or less the same (this will depend on the amount of brazing done for a particular business). However, what is the price of Safety and of your life ?

7.Can a big output Safeflame unit be used with multi-drop off points for many torch terminals ?

Unlike many HHO flame from water system which pipes combustible gases (Hydrogen and Oxygen) for example around the factory, Safeflame do not approve of it. In addition there are strict guidelines in piping combustible gas mixtures which needs to be complied with. In addition if there is a problem with the unit supplying the combustible gases to the various terminals, the whole work application area will have to stop. Safeflame advocates the use of multiple smaller Safeflame units to be more efficient and safer.

8.Can Safeflame system be used to braze Aluminium or Aluminium to other metals like copper ?

Safeflame is ideal for brazing Aluminium to Aluminium due to the softer Hydrogen Flame. It is particularly great for brazing Aluminium to copper or other metal. It is much more difficult with Oxy-acetylene and one has to be very skilled to do that. One can also braze Aluminium with Oxy-propane but that involves compressed gas bottles.

9.Can Safeflame system be used for cutting metal ?

Safeflame unit can be used for cutting metal only in conjunction with compressed oxygen which does the actual cutting but that defeats the Safeflame object of "not using compressed gas bottles". Safeflame is mainly used for brazing and flame polishing applications. The hydrogen flame is softer and wraps round the pipe for easier brazing compared to other forms of brazing fuel gases and it is much safer.


In addition, the brazing process is being "de-skilled" due to the ease of use of the Hydrogen flame from the Safeflame unit. The temperature of Hydrogen flame is around 2700C compared to Oxy-acetylene of 3300C.


Existing HHO systems in the market today which are also a form of "Flame from water" uses a "booster" by bubbling the HHO gas mixture through an alcohol like MEK or Acetone to give the flame a bit of colour. However, the resulting flame is no longer a pure Hydrogen flame, instead it is a hydrocarbon flame with lower temperature and not so kind to the environment.

10.Can Safeflame units be joined together safely to produce higher Hydrogen and oxygen outputs system ?

Safeflame has been designed to be able to couple together to produce higher Hydrogen and Oxygen outputs. In most applications, a smaller Hydrogen output unit will cope with about 80-90% of their normal day to day requirements. However occasionally higher Hydrogen output may be required and the coupling up of units comes in very handy.


For example, if an organisation has 2 units of Safeflame with standard output of 4.5LPM each which can be boosted to 6.5LPM. Joining the 2 units together gaseously with non return valves on each unit gas pipes it will be able to produce a standard output of 8LPM and when boosted, it will produce 13LPM. That output will be able to braze pipe sizes up to 1 5/8". There is a video in the Gallery Section demonstrating this facility.​

11.Can the Safeflame unit produce a less than stoichiometric mixture of Hydrogen and Oxygen flame ?

All Safeflame units have the facility to dump some of the Oxygen produced from the process of electrolysis of water. Therefore it can produce a less than stoichiometric gas flame.

This may be particularly useful for certain application where less oxidation is required. A good example will be the brazing of silver or glass beads that uses some silver compound.

Safeflame can reduce the oxidation of the silver and can prevent the finished piece from turning black due to formation of silver oxide.