How to weld like a pro
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BASICS OF STICK WELDINGStick welding refers to a welding method where a filler rod in the electrode holder serves as the welding electrode. The arc burns between the rod and the workpiece. The difference to other welding methods is that the filler rod that serves as the welding electrode in stick welding shortens continuously as the welding progresses. In MIG/MAG welding, the distance of the torch from the workpiece must remain constant at all times. In MMA welding, however, the electrode holder must continuously be brought toward the workpiece to keep the distance between the electrode and the molten weld constant. This presents special challenges for Stick welding.
STICK WELDING APPLICATIONSStick welding can be used under almost any conditions, and therefore it is a rather universal method in the welding industry. It is commonly used in installation worksites where good reachability is required for welding machines and where work is often done in outdoor environments. It is a common welding method for example in welding power plant pipelines and other pipe welding sites. It is also a welding method favoured by hobbyists and small repair shops. It can also be applied in underwater welding, where fillers designed particularly for underwater environments are used.
STICK WELDING MACHINESStick welding requires a power supply, a ground cable, and a welding cable equipped with the electrode holder. There is no shielding gas, as the welding electrode is coated with a material that produces shielding gas and slag over the molten weld pool. Today’s small inverter power sources further increase mobility and reachability. The power supply can, for example, be connected to a generator with long input cables, taking the welding machine next to the workpiece. The smallest power sources currently weigh only 5 kg. Stick welding is rather popular in hobbyist use as the only required parts are the power source and the filler material rods. No shielding gas is required, and the devices usually operate with the current obtained from a regular residential power outlet.
STICK WELDING ELECTRODESA welding electrode also known as welding rods, is a fixed-length, straight welding wire coated with a filler material. The welding electrode is a fixing head with which it is attached to the electrode holder. The other end of the electrode has the ignition head with which the workpiece is stuck to ignite the arc. The diameter of a welding electrode refers to the diameter of the metal rod inside the electrode. The purpose of the coating on the surface of the metal rod is to protect the welding event from the effects of the surrounding air, to produce slag to support the weld, and to make the creation of the arc easier.
STICK WELDING TECHNIQUEBefore welding, it is recommended that one check the condition of the welding power source, the cables, electrode holder, and the grounding clamp. If the power source has a control panel and remote control, their functionality should also be reviewed. The quality and strength of the welding electrodes must be checked and they must match the workpiece. The coating on the electrode must be intact. The welding is started by sharply striking the bottom of the groove with the welding electrode. After this, move the welding electrode back to the beginning without stretching the arc, and move the electrode easily while monitoring the width of the molten weld pool. Move the welding electrode with the handle pointing forward. The boundary of the slag formed is visible after the molten weld. It must be behind the molten weld. The distance of the slag boundary from the molten weld can be adjusted with the welding current and the angle of the electrode holder. Throughout the welding, concentrate on the length of the arc and keep it as short as possible. The length of the arc increases easily as the electrode decreases in size during the welding. The movement may be somewhat difficult to control at first but it is easy to get accustomed to, When the welding electrode runs out, one needs to remove the slag from the previous weld and clean it with a steel brush. Ignite the next electrode slightly ahead of the previous weld and then move the welding electrode back to the previous weld and continue with the welding. Turn off the welding electrode by moving it slightly back to the completed weld and then lifting the electrode straight away from the workpiece.
In MIG/MAG welding, an arc is created with the power supply through the welding gun between the welding wire being fed and the work piece. The arc fuses the material being welded and the welding wire, thus creating the weld. The wire feeder continuously feeds welding wire through the welding gun throughout the welding process. The welding gun also provides shielding gas to the weld.
The MIG and MAG welding methods differ from each other in that MIG (metal inert gas) welding uses an inert shielding gas, which does not participate in the welding process, while MAG (metal active gas) welding employs an active shielding gas that participates in the welding process.
Usually, the shielding gas contains active carbon dioxide or oxygen, and therefore MAG welding is by far more common than MIG welding. In fact, the term MIG welding is often accidentally used in connection with MAG welding.
MIG WELDING APPLICATIONS
Today, MIG/MAG welding is used nearly everywhere in the welding industry. The largest users are heavy and medium-heavy industry, such as shipbuilding, manufacturers of steel structures, pipelines, and pressurized containers, as well as repair and maintenance businesses.
MIG/MAG welding is also commonly used in sheet metal industry, particularly in the car industry, body shops, and small industry. Hobbyists and home users also most commonly have a MIG/MAG welding machine.
WELDERS AND OTHER EQUIPMENT FOR MIG AND MAG WELDING
MIG and MAG welding equipment is typically comprised of a power source, wire feeder, grounding cable, welding gun, optional liquid cooling unit, and a shielding gas tank or gas network interface.
The purpose of the wire feeder is to feed the welding wire needed in welding from the spool coil to the welding gun.
The wire feeder also allows for starting and stopping the power source and, when using an electronic power source, control the voltage provided by the power source. Therefore, the power source and the wire feeder are connected with a control cable. Additionally, the wire feeder controls the flow of the shielding gas. The shielding gas needed in welding is obtained either from a gas tank or from a gas network.
MIG welding machines are often modular in structure, and the cooling device, power source, and wire feeder can be freely selected according to the requirements. The wire feeder can be detached from the power source, thus making it unnecessary to move the entire welding machine from one worksite to another.
The devices may also have a replaceable control panel and separately activated additional features.
The welding gun heats up during welding, and therefore it must be cooled with gas or liquid. In gas-cooled welding guns, the shielding gas running to the gun through the welding cable simultaneously acts as the gun cooler. In liquid-cooled guns, a separate liquid cooling unit is required to recycle the cooling liquid within the welding cable to the gun.
MIG WELDING TECHNIQUE
In MIG/MAG welding, the welder’s tool is a welding gun. It is used to introduce the filler material wire, shielding gas, and the required welding current to the work piece. The most important issues related to MIG/MAG welding are the welding position, welding gun angle, wire stick-out length, welding speed, and the shape of the molten weld pool.
The arc is ignited with a trigger in the gun, and the gun is then moved at a steady welding speed along the weld groove. The formation of the molten weld must be observed. The position and distance of the welding gun relative to the work piece must be maintained constant.
It is particularly important that the welder concentrates on managing the molten weld at all times. A moment of wandering thoughts increases the risk of welding errors. In such cases, it is advisable to interrupt the welding for a moment and then resume.