Dissolved Acetylene (C2H2)

Features of Dissolved Acetylene:

• the hottest and most efficient of all the fuel gases, providing high levels of productivity
• very efficient use of oxygen
• lighter than air and will not accumulate at low levels
• low ignition energy
• low moisture content flame
• non-toxic (may cause dizziness in high concentrations)

Benefits

• oxygen and acetylene together produce a flame temperature of approximately 3150°C
• the oxy-acetylene flame gives very good localised heating with a minimum of wasted heat
• in cutting, oxy-acetylene gives the fastest preheating and piercing times of any fuel gas combination
• in oxy-acetylene cutting processes, improved cut quality, higher cutting speed, faster cut initiation time and reduced oxygen use are achieved
• when used with either oxygen or air, acetylene can produce a thin layer of black carbon particles.  This can prevent components sticking in their moulds
• unused gas will not collect in low-lying areas, ducts and drains causing a potential hazard
• acetylene is stored in specially-designed cylinders to prevent decomposition
• the flame has a low moisture content making it a good choice for many critical heating applications

Application and use

• cutting
• flame heating
• flame gouging
• gas welding.  The only fuel gas which can be used to weld steel
• flame hardening.  An oxy-acetylene flame can be used where the hardened surface of carbon steel components is either in situ as a remedial process or on components too large to fit in a furnace
• flame cleaning.  A wide oxy-acetylene flame is held very close to a steel surface to be cleaned
• flame straightening where the precise and efficient flame properties are used to remove distortion in plate material
• thermal spraying of various metals and ceramics.  The material to be sprayed is fed through the flame
• spot-heating applications
• brazing
• texturing
• profile-cutting
• branding wooden pallets
• wood-ageing
• glass and metal castings
• mould release and other anti-stick applications
• the only fuel gas recommended for use in underground working conditions

Please note:  in any confined spaces, extraction devices should be used to remove any potentially dangerous by-products.

Material compatibility

Acetylene can ignite and burn instantly from a spark or piece of hot metal.

It can form explosive acetylide compounds with some metals, most notably copper, silver and mercury. 

Please note:  copper alloys containing less than 65% copper and silver solder containing less than 43% silver are considered safe.

Hoses used with acetylene are coloured red and are designed to resist acetone.  For this reason other fuel gas hoses must not be used.

For a full list of materials which are not allowed or are recommended only under certain conditions, please consult BCGA Codes of Practice CP5 and CP6

Hazards

• care must be taken when using acetylene as it is an asphyxiant
• acetylene is highly reactive.  It is dissolved in acetone and contained within a porous mass inside the cylinder
• acetylene can react over time with some metals to form explosive acetylides
• acetylene is slightly lighter than air and will collect at ceiling level