It's the best "superglue" in the world

Most people think of welding like it was Black Magic Voodoo, something that only highly trained professionals can do with equipment worth more than a car. In fact welding can be performed with as little as a car battery, a wise grip, jumper cables and a welding rod. What is also supprising is that generally the more advanced your welding machinery the easier it is to make good welds. When described welding is nothing more than applying intense heat to a small area so that the metal in this area is joined seamlessly. The source of the heat and method of applying it is where the methods differ, each combination has a role. There are currently four heat sources used in welding, electric arc, gas & oxygen flame, chemical reaction and mechanical.

	1. Mechanical welding is the art of using extreme pressure (think hydraulic) to such a degree that the materials are fused, the pressure creates the heat required to "micro weld" the materials.
	2. Chemical reaction is where two powdered metals are ignited to start a reaction where one of the metal is liquidated while the other is oxidized, often referred to as "Thermite". Thermite is most commonly made of oxidised Iron (rust dust) and aluminium powder, these two burn at over 1500 °C (2732 °F, 1773 °K) producing liquid steel which welds the materials it comes in contact with. This is a rarely used method, applied in emergency cases or where underwater welding needs to be done.
	3. witch it can also be used to "Burn Steel", where high velocity pure oxygen is used to cut the steel by oxidation. The great thing about gas welding is that the burned gas automatically shields the metal from oxidation.
	4. Electric Arc welding is by far the most popular, there are in fact four sub-methods that make up this category. The Ground is common to all electric welding, the ground is a return path for the electricity that is used to heat the metal (although the polarity can be positive or negative). The amount of heat formed is controlled by a current control at the welder.
	4.1 "Stick Welding" is the oldest and still most popular welding method around, it requires only an electric transformer, a rod holder with leads and a flux coated rod. To initiate a weld the far end of the rod has to touch the workpiece before being pulled back to form an electric arc. This arc formes a weld puddle which is maintained and slowly moved across the seam while the rod slowly deposits metal into the weld puddle that is formed. The rod is coated with a material called flux. The flux is a combination of chemicals that when heated, creates a gas shield around the molten puddle to prevent atmospheric contamination and oxidation, and a liquid substance that forms a coating over the weld once it solidifies, protecting it while it cools.
	4.2 "MIG Welding" also referred to as GMAW (gas metal arc welding) automatically feeds a small diameter wire onto/into the work material, this wire is protected by a stream of inert gas (argon/helium/co2) ejected from the same nozzle. The speed of the wire and the current can be controlled from the welder. This is the fastest welding method and is replacing stick welding as the most popular. The benefits include a cleaner weld area (no flux), less distortion* due to more concentrated heat and ease of use.
	4.3 "TIG Welding" also referred to as GTAW (gas tungsten arc welding) is where a non-consumable tungsten rod is used to conduct electricity to the work piece by means of an arc, the tungsten rod is protected by an inert gas similar to a MIG setup. Unlike the other methods the rod does not become a part of the weld and it is therefor possible to weld without adding material. This is the preferred method for welding aluminium, tungsten and most alloys due to precise control, good protection and minimal risk of weld contamination**. When needed a filler wire of the same type as the base metal is fed into the weld puddle with your second hand.
	4.4 "Plasma Welding" is the second generation of tig welding. Instead of creating an arc from the tip of your tungsten electrode to the work piece a plasma torch is used. The plasma torch generates an arc internally between two non-consumable electrodes, these electrodes are protected by a stream of inert gas. As the gas passes the electrodes it is superGas & Oxygen welding is most often perfomed with acetylene and oxygen mixed to exact proportions and burned in a special torch. The reaction creates a flame that is between 2500 °C (2773 °K, 4532 °F) and 3000 °C (3273 °K, 5432 °F). This flame can be used to melt and join metal pieces or if the torch is fitted with a cutting sheated (c.a. 20.000 °C, 36032 °F, 20273 °K), this plasma gas is directed towards the work surface while surrounded by an inert shielding gas. Plasma welding is the most precise, least distorting and most expensive form of electric (resistance) welding. It is mostly used for airospace, nuclear powerplants and such. Plasma cutting uses the same technique except the gas has a higher velocity effectively blowing the hot metal away.

For more information on welding Lincoln Electric has a great knowledgebase with tons of articles located here www.lincolnelectric.com/knowledge/articles/

* Distortion is when the metal pieces develop internal stresses which cause the metal to warp. It happens because when a metal is heated is expands, when a area expands without the possibility to detract when it cools internal stresses are formed.

**When unwanted materials/gasses penetrate the shield and cause defects in the metal