There are a variety of different types of gases that are used in welding. One of the major ways that gases are used is for shielding the area to be welded from gases that come from the atmosphere. The reason the shielding area needs to be welded is because these other gases can change the way the weld looks or make it difficult to use.Whether a gas is used, the type of gas, and how it is used will be determined by the welding process that is used. Some of the most common gases and their uses are listed here:Acetylene Gas -- this is a flammable gas that is also colorless and some people say it smells like garlic. The periodic table designation is C2H2. This gas gets the hottest of all hydrocarbon gases because it has a structure that is called triple bon. When you combine this gas with oxygen, which is how it is often used, the temperature of the flame can get as high as 5580 degrees Fahrenheit. This gas can be used for small or large projects. This gas is often called Oxyacetylene when it is also combined with oxygen.Uses: bracing, pipe welding machine, cutting and soldering and they are usually stored in pressurized steel cylinders.Air -- believe it or not air is considered a gas in a welding situation. Air is found in bottles and is often compressed for the purpose needed in welding.Argon -- this is a nontoxic, nonflammable and inert gas which means that it doesn't have a chemical reaction when it comes in contact with metal or other material. This is also a colorless gas and doesn't carry an odor.Uses -- it is basically used for arch welding, the manufacturing of electronics, making steel and heat treating. Also used to weld aluminum and stainless steel (when combined with oxygen).Oxygen -- is primarily used to work with other gases where high heat is necessary to do the weld. It is most often used with acetylene but it can also be mixed with argon and other types of gases.