Gas tungsten arc welding (GTAW) uses a tungsten electrode to make a weld and is a kind of arc welding. It is also called tungsten inert gas (TIG) welding. This method can be used on steel or on aluminum but is much more difficult to use on aluminum. There are many reasons why aluminum is so much more difficult to weld.
When welding aluminum certain things have to be done. The machine has to be clean, the settings have to be correct, the tungsten electrode has to be clean, the arc length has to be right, the torch and filler rod angle has to be just so, the correct kind of electrode has to be used and the arc size and length has to be perfect. Complicated, isn't it?
Some things to know about aluminum that will help ensure the process goes as smoothly as possible:
1. If aluminum has been left outside, it is heavily oxidized. This could be things such as a boat propeller. Make sure that you clean it thoroughly or it would be like welding a firework!
2. The machine's settings have to be correct. The machine needs to be on alternating current and the high frequency switch should be set at continuous. If you don't have the settings like this you will have a stuttering arc.
3. The amperage will have to be adjusted with aluminum. Aluminum conducts electricity and the amperage has to be controlled in order to heat it properly. The foot pedal is perfect to control the amperage. It can be pulsed to help avoid heat buildup and will keep your welding from looking like a stack of dimes.
4. If you are welding steel, then the length of the arc has to just be more or less correct. Yet when you are welding aluminum, it has to be perfect. If the arc is too short the metal could jump on you and if it is too long the heat will disperse. It could contaminate your rod.
5. Always make sure the rod and metal is as clean as you can make it. Aluminum is not like steel. A little amount of dirt on the electrode will not cause a lot of problems when welding steel, but it will make the weld sooty if you have a tiny bit of dirt on the electrode when welding aluminum. You would have to start all over again.
6. Hold the torch at the proper angle. Make sure that you do not have too much of an angle or the filler rod's tip will met and you will end up with a puddle made out of the filler wire. This will happen in steel welding too but not as badly as it will with aluminum.
7. What kind of tungsten electrode you use makes a difference. If you are using a newer kind of TIG welder inverter this is especially important to remember. Never use pure tungsten with the new inverters because it could damage the welding machine itself.
8. The size of the tungsten electrode is also very important. You need to use different rods and which rod you use depends on how thick the metal is. When working with aluminum, always keep 1/8”, 3/32”, and 1/16” rods nearby so that you can change them quickly.
Welding aluminum requires more care and you may have to practice before you get the hang of it. Yet it is a valuable skill to have and one that can make any welder especially valuable.
