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How To Weld Aluminum

Even if you are experienced in welding steels, learning how to weld aluminum can still be quite a challenge. The oxide coating, lower melting point and high thermal conductivity, can lead to problems unless you know to do through preparation and setting up the equipment.

  Learn to Weld Aluminum Like A Pro

While mig welding is used extensively in fabrication industries such as boat building, the most applicable for lighter gauge aluminum is tig welding both for strength and cosmetic appeal.

Welded aluminum is used for such applications as aluminum bicycle frames, wheel chairs, fencing and balustrades and aerospace work, also commercial airline engine casings, seat frames, ductwork, and any-where else where lightness and strength is required.

To weld aluminum, two main processes are generally used, Mig (GMAW) or Tig (GTAW) each uses different equipment and methods.

Mig & Tig Filler materials

Tig aluminum filler material is available in short easily handled lengths of about 500mm long, where as mig filler is aluminum welding wire on a feed spool, both come in various size diameters depending upon the aluminum to be welded. Keep filler material dry and free from oxidation and other contamination.  If you use your mig welder for welding steels and aluminum you will need to replace the inner cable liner and welding tip each time you switch processes, aluminum liners are usually made of Teflon, where as a metal liner is also metal. Using aluminum wire in a metal liner will result in contamination of the weld.

Work preparation

Aluminum work must be cleaner than steel work pieces to be welded effectively. The first step is to remove oils and greases from the work piece by wiping the area with a solvent or washing it with a mild alkaline solution. The second step is to remove all oxides, which can be done with a stainless steel wire brush. Never use the same brush on aluminum and steel or it will become contaminated.

Not only do you need to clean well before beginning, but you also should remove the smut or soot between  passes. This soot is fine particles of aluminum oxide and magnesium oxide. Proper welding techniques will minimize the amount of soot produced.

Shielding Gas

usually, 100 percent argon gas is preferred for aluminum GTAW, but when working with thicker materials, such as 1/2 inch or greater, add helium in the range of 25 to 50 percent. Helium makes the arc hotter and provides for more penetration.

Torches and mig guns

if the application is light-duty fabrication requiring up to 150 amps, an air-cooled torch or hand piece may suffice. Higher-amperage jobs require a water-cooled torches and hand pieces. One feature to look for in a good torch is a flexible head, which offers maneuverability and reaches tight areas. Trying to access tight areas is a main drawback to using a mig set-up due to the size of the gun or hand piece.

When you learn how to weld aluminum, you can reduce the number of errors you make by learning  to set up your welder using proper gasses, wire feeds, and electrodes and using correct preparation of your work. Plus getting  advice from tutorials and more experienced welders. In time, you will feel as confident welding aluminum as you do steel.


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