5 Tips for TIG Welding Aluminum
TIG welding aluminum is a high end fabrication process used by most professional and expert welders. It is also something that many home hobbyists would love to learn. Tungsten Inert Gas (TIG) welding involves using a non consumable tungsten electrode. In this process, only the filler rod and aluminum are introduced to the welding puddle. As simple as it may sound, TIG welding aluminum requires a lot of skill and patience. Following are some important tips for TIG welding aluminum that can help any welder.
Clean the Base Material
One of the most important tips in TIG welding aluminum is cleaning the base material properly. This means removing any traces of aluminum oxide from it. Leaving oxide on the base material will not allow the filler metal to penetrate into the work piece properly. Aluminum oxide can be removed from the material by brushing it with etching solutions and solvents or a stainless steel wire brush. If you are using the latter, take care to brush it in one direction and avoid brushing it roughly.
Preheat the Work Piece
In TIG aluminum welding, pre-heating a work piece can prevent weld cracks from occurring. Ensure the pre-heating temperature does not go over 230F. Using a temperature indicator can be quite helpful to prevent overheating. As aluminum is a strong conductor of heat, you may require great heat input when starting a weld. This is because a lot of heat is lost when the surrounding base material is heated. It is better to place tack welds at the start and end of the place that has to be welded.
Fast Travel Speed
TIG aluminum welding is best performed at a faster travel speed and higher temperature. Aluminum has higher thermal conductivity compared to steel. This is why it needs higher weld travel speeds, hotter voltage settings and amperage. A travel speed that is too slow can put the work piece at a risk of excessive burn through. This is especially true when it comes to a thin gauge aluminum sheet.
Choose a Good Welding Wire
There are different types of aluminum filler wires that can be used for different base materials. It is important to choose an aluminum filler wire that has a melting temperature similar to that of the base material. The more you narrow down the metal’s melting range, the easier it will be for you to weld the alloy.
Use Suitable Shielding Gases
A shielding gas is continuously provided through the torch for protecting the tungsten electrode, filler wire tip and molten weld metal from air contamination. The most common gases used are Helium and Argon or a mix of these two. These gases are good because of their cleaning actions and their penetration profiles. When you extinguish the arc at the end of the weld, shield the hot metal from the air by allowing the gas to flow on it for some time. This will allow the metal to cool and protect it from any damage.