These mig welding instructions are an overview of mig welding. Commonly refered to as gas metal arc welding (GMAW) or mig welding, this type of welding is today the most popular and versatile method of welding. Mig welding is used in production and maintenance work and can be applied to both heavy engineering and construction work to auto body work. Mig welding is perfect for day to day factory work as well as being the perfect welding method for the home workshop.
Mig welding uses a welding power source and a wire feeder that feeds the wire electrode through the welding gun to the weld. The wire electrode comes in various coil sizes or spools depending on the welder size, that contain hundreds and even thousands of feet/meters of wire. The wire feed consists of a set of drive wheels for the wire and a constant speed motor to turn the drive wheels. Most Welders have various functions allowing timed feeds and variable speeds.
The wire is feed through a shielding gas hose and cable that allows the electrode to run smoothly without bending or kinking. The wire is sheilded during welding by an inert gas such as argon. Welding wires can differ with solid wires used for aluminium, stainless steel and mild steel, but also flux cored wires are also used. A gasless wire is avaliable for mig welding mild steel, this is usefull in outdoor situations where breezes are a concern by blowing away the protective gassae.
Inert gasses are gasses that will not react with metals or other gasses. With mig welding Inert gases are used to create a protective bubble around the arc and molten metal while the welding is being done. This gas is generally pure argon gas for welding aluminium and argosheild gas for mild steel applications.
Mig welding can be used for steel, stainless steel and aluminium welding, all require slightly different gasses welding wires, and amperage settings. and due to the work requirements the heavier the metal being welded the more powerfull welding machine needs to be.
Mig Welding Mild steel
Mig welding mild steel is generally the easyest method of welding , with many different welders avaliable today the home welder can set up a home workshop and with a little tuition be carrying out repairs or working on various constructional projects.
Mig Welding Aluminium
Even for those experienced in welding steels, welding aluminum can present quite a challenge. Higher thermal conductivity and low melting point of aluminum will easily lead to burnthrough unless welders follow prescribed procedures. This is particulary on thinner sheet aluminium. Feeding aluminum welding wire with mig welders presents a challenge because the wire is softer than steel, has a lower column strength, and tends to tangle at the drive roll. Using aluminium in a mig welder also requires the "linner" inside the welding cable to be changed to teflon, allowing smoother travel and less friction .
Mig Welding Stainless Steel
Although welding stainless steel may not be as difficult as welding aluminum, the metal does have its specific properties that vary from your more common steels. When MIG welding on stainless, you usually have three choices of transfer depending on your equipment: spray-arc, short-circuiting, or pulsed-arc transfer. A more specialised method for welding stainless steel is tig welding.