Traditional Gas Welding
Gas Welding, also called oxyfuel welding, is a system of welding that uses various gases and oxygen to ignite a torch. Gas welding is one of the oldest welding processes and is performed by mixing oxygen with acetylene to produce a flame that is 3000⁰C. Welding is defined as the process of combining two materials, usually metal, by heating them until both ends become molten. Filler materials are generally added into this molten material and the two ends are joined together and allowed to cool, forming one solid piece.
Common gases used in gas welding include natural gas, propane, hydrogen, MAPP gas, liquefied petroleum, propylene and acetylene, with acetylene being most common. In many cases one gas is not superior to another although in some situations a specific gas may heat higher or lower than another, making it more convenient to use with certain metals.
The gas welder is generally constructed using two tanks. One holds a specific type of gas, which is usually unique to each manufacturer, and the other holds oxygen. These two gases combine as they enter the torch and help maintain a consistent flame.
There are other uses for the oxy fuel torch, many of them involving materials other than metal. Gas welding torches can be used to cut metal and to flame stone for decorative purposes. There are also specialised water welders that are used for welding very small and delicate objects like jewellery, or for fire polishing glass. They can also be used to heat quicklime in order to create a bright light – and these are often used in magic shows and other productions.
Another type of gas welding involves the use of a single gas without the use of oxygen. This method is generally not preferable for many types of metal but is commonly used in soldering. Soldering is an easier form of welding that is performed by melting solder and using molten material to join two pieces of metal. This differs from traditional welding because the two pieces are not melted, but are conjoined by solder. The soldering method is not recommended for large items or welds that need to withstand high levels of pressure, but works well for the inner workings of electronics and other small applications.
Inert Gas Welding
Inert gases, or noble gases, are gaseous elements in the helium group of the periodic table which are considered chemically non reactive. These gases, which do not form chemical compounds, include helium, neon, argon, krypton, xenon and radon. Inert gas welding is a welding process which uses an inert gas to protect the weld during the welding process.
During the welding process an electric arc is struck between the electrode of the welding equipment and the work piece. This arc creates heat which fuses the edges of the metal pieces being joined, as well as any consumable electrode being used, thus forming the weld joint. The gases used in inert gas welding include argon, helium, carbon dioxide or a combination of gases like argon and oxygen.
Metal inert gas welding (MIG) uses a consumable electrode or a solid electrical conductor made of filler metal wire. An electric arc forms between the electrode and sheet metal being welded, and inert gas surrounds the weld to protect it from oxidation. This method works with carbon steels, low alloy steels, stainless steels and most aluminium, copper and zinc alloys. MIG welding can be used to weld metals with a thickness ranging from two-tenths to one quarter inch (5mm- 6.3mm).
Tungsten inert gas welding (TIG) uses a non consumable electrode made from tungsten. Unlike MIG welding, tungsten welding does not require a filler material. This method can be used on the same metals as MIG welding, but it does a better job of welding dissimilar metals together. One advantage of TIG welding is that it can join pieces as thin as five-hundredths of an inch (.125mm) together. The location and cosmetic importance of the weld will help determine which form of inert gas welding to use for a particular application. MIG welding is less expensive and does not require a high level of expertise from the operator. The weld is messier, however, because of the use of a consumable electrode or filler material. If the weld is in an area which is visible, MIG welding is generally not recommended because it causes a lot of spatter which will need to be sanded or filled.
TIG is a bit more expensive than MIG welding but is the recommended method if appearance is important as there is no spatter created during the weld – that’s because a non consumable tungsten electrode does not use any filler material. This method requires a high level of operator training and expertise. Argon is the most commonly used gas for TIG.
Inert gas has been used since the 1940’s and provides faster results than traditional welding methods. It can produce cleaner, longer and continuous welds, especially with thinner materials. One drawback of this form of welding is that the equipment is less portable and more expensive than other gas welders. Another limitation is that inert gas welding must be done inside and not in an open area where the wind can interfere with the protective gas shield.
Gas Welding Complete kits
Gas Welding Accessories
Welding Safety Equipment
Gas welding is a dangerous process so it is important that you protect yourself with a combination of welding safety products:
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