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Oxyacetylene is a gas welding process using acetylene and oxygen. See also Oxy-fuel welding and cutting. Wikipedia does not have an article with this exact name. ... Compressed gas cylinders containing oxygen and MAPP gas. ... Oxy-Fuel Welding is a welding process commonly called Oxy-Acetylene Welding, since acetylene is the predominant choice for a fuel, or often simply Gas welding. ... The chemical compound acetylene, also known under IUPAC nomenclature (see IUPAC nomenclature of organic chemistry) as ethyne, was discovered in 1836 by Edmund Davy, in England. ... General Name, Symbol, Number oxygen, O, 8 Chemical series Chalcogens Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Compressed gas cylinders containing oxygen and MAPP gas. ...

An oxyacetylene torch can also be used for cutting metal by heating the metal until it glows and then pressing a lever on the torch which allows an excess of oxygen to be added to the gas mixture. The mixture is used because of the high temperatures that can be reached. The top torch is a welding torch and the bottom is a cutting torch, or blowtorch A blowtorch is a torch used to cut metal. ... Temperature is the physical property of a system which underlies the common notions of hot and cold; the material with the higher temperature is said to be hotter. ...

How to operate an oxyacetylene torch

If you have not been trained in oxyacetylene welding or brazing, seek out the assistance of a knowledgeable person or enrol in a community college course. Oxyacetylene welding is not difficult, but there are a good number of subtle points that should be learned such as: never fully empty an acetylene cylinder or use more than 1/7 the capacity of the cylinder per hour. The material below highlights many of the important points but should be supplemented by personal instruction and a good welding text.

Safety Considerations

Welding is a practical and satisfying art, however, oxyacetylene welding is potentially dangerous activity. Severe and fatal burns and violent building destroying explosions can result from inattention and carelessness. Familiarize yourself with safety procedures and weld safely!

Before using an oxyacetylene set, ensure that flammable materials such as grease, oil, paint, sawdust etc are cleared from the area and workpieces. Oil and grease can spontaneously ignite and burn violently in the presence of pure oxygen. For this reason it is important to wear clean, oil and grease free clothing.

The fluxes, filler rods and base metals heated during welding and brazing all release toxic fumes and acetylene gas is highly explosive so ensure adequate ventilation before welding. Acetylene is often described as having a sweet garlic like smell. If you can smell it in the air and don't know where it is coming from, evacuate the area immediately. Call the fire department from a phone *outside* of the area as a phone can set off vapours. In confined spaces, respirator masks designed for welding can be used. For the home welder, an outdoor area is probably the most practical, though the weld site should be protected from winds as this will disperse the heat of the flame. Never weld on containers that have previously contained toxic or flammable substances. Do not weld inside enclosed spaces or in tanks where the only ventilation comes from above - you might suffocate.

Leather gloves with long cuffs and heavy work boots are recommended. Falling droplets of metal will instantly burn through running shoes and continue burning through the operators foot. Long pants and shirt sleeves should be worn. Do not role up pant legs as the cuffs could catch sparks. Leather aprons and flame proof jackets can be used to protect the operator. Many operators use a baseball cap put on backwards to prevent sparks from lodging in hair or going down the neck of their shirt. Eye protection is also necessary. Gas welding does not generate the same UV as arc welding but sparks and infra-red radiation are still very dangerous. Safety gear such as shaded protective goggles should be adjusted before lighting. For brazing and light welding "shade 5" goggles can be used. Note, gas welding goggles and arc welding masks are not the same!

Before using an oxyacetylene setup, ensure that a fire extinguisher in good working order is present. Water does not work on grease fires, however a bucket of water can be handy for putting out small wood fires and quenching parts. A wet cloth can also be used to extinguish a flame on a hose or fitting. Sand can also be used to put out fires. It is also generally handy to have at least one pair of heavy pliers around for moving hot things if necessary. Be sure your workspace is well organized before starting. Have tools laid out where they can be easily reached and make sure there are no tripping hazards. A fireproof surface should be used for welding. Steel table tops and fire bricks are commonly used.

Ensure that the tanks are secured vertically on a cart or chained to a wall. If the cylinders were to fall over and the valve broken off the top, the highly pressurized gases inside will convert the cylinders into rockets capable of smashing through walls. On your oxyacetylene torch system there will be three types of valves, the tank valve, the regulator valve, and the torch valve. There will be one of them for each gas. The gas in the tanks or cylinders is at high pressure. Oxygen cylinders are generally filled to something like 2200 psi. The regulator converts the high pressure gas to a low pressure stream suitable for welding. Never attempt to directly use high-pressure gas. Do not use pressurized oxygen for blowing dirt out or cleaning clothing. The oxygen can saturate the material making it eight times more flammable! A valve is a mechanical device that regulates the flow of fluids (either gases, fluidised solids, slurries or liquids) by opening, closing, or partially obstructing various passageways. ...

Know how to contact emergency services at whatever site you are working.

Lighting a setup torch

Here are the steps:

1. Read the safety considerations
2. Reread the safety considerations
3. Ensure that the hoses are untangled and kept well clear of the flame. It is a good practice to give the hoses a quick inspection for cracks and abrasion before use. Generally, tanks are set up behind the welding area and hoses run backwards away from the weld site to minimize chances of sparks hitting hoses.
4. Make sure that the regulator valves are turned all the way out and the torch valves are closed.
5. Open both tank valves. The valves should be opened slowly to minimize the impact of unleashing highly compressed gases on the regulators. The operator should not stand directly in front of the regulator guages as malfunctioning guages can blow outwards. The oxygen tank valve is a backstop valve and should be opened all the way in order to completely seal. The acetylene valve should only be opened a 1/2 turn. Make sure the valves are easily accessible in case emergency shutdown is necessary.
6. Turn both regulator valves inwards until you reach the desired pressure.
   • For welding with a smaller tip (size 0), use 5 psi for the oxygen and 5 psi for the acetylene. For other tips consult a welding reference. For larger sized tips it is important to make sure that you do not draw more than 1/7 capacity of the acetylene tank per hour.
   • For cutting, use 15 psi for the oxygen and 8 psi for the acetylene.
7. It is recommended that you purge the gas lines before use to ensure that no oxygen is in the acetylene line and vice versa. Ensure that you have adequate ventilation. For a 20 foot hose, open the torch valve for 5 seconds to allow oxygen to bleed from the line acetylene line. For a longer hose, consult a welding reference. Close the torch valve and repeat for the other line.
8. If the setup has not been used in a while you may wish to check for leaks. With the torch valves closed and the regulators open, shut off the tank valves and observe the line pressure for several minutes. If the pressure falls, there is a leak in the system. Bubble solution can be used to test connections for leaks. Never use a setup with a leak!
9. Open the acetylene torch valve a very small amount (1/4 turn) and light with a spark lighter.
10. Once the flame is lit, open the acetylene valve just until the flame stops smoking. You should get a flame about 8 inches long with a toothy splintering end.
11. Now open the oxygen valve until the flame loses its feather around its inner core, but no farther than this amount. This is called a "neutral" flame. The mixture of oxygen and fuel gas combine to produce exhaust gases that do not chemically alter the metal to be welded or brazed.

NOTE: DO NOT SET THE ACETYLENE REGULATOR VALVE HIGHER THAN 15PSI! If you do, the acetylene can explosively decompose into carbon and hydrogen gas all by itself.

To shut down the torch, close the oxygen torch valve first, then the acetylene. A 'pop' may occur if you reverse the order. The pop throws carbon soot back into the torch, which may partially plug the gas passages. Next, close both the tank valves. Turn on the torch valves again, one at a time, to bleed any remaining pressure, then close them again. Lastly, turn the regulator valves until there is no pressure on the adjusting spring and the screw turns freely.