Like with most metals, if you have decided that you would like to use aluminum, you will need to next decide what type of aluminum you would like to use. The most common aluminum alloy for general purpose is 6061 aluminum because it is very versatile. 6061 is popular because it has good weldability. However, even with its weldability, it is possible to make certain mistakes.
Don't Choose Your Aluminum Just Based On Strength
One mistake is to choose the aluminum alloy based only on its strength rather than on other characteristics, such as its ability to deflect. If the aluminum alloy is the strongest possible, but does not have elasticity necessary to deflect various pressures, the aluminum is more likely to experience structural problems. Fortunately, 6061 does not usually have this problem. Make sure you are aware of how strong the aluminum alloy is because, unlike with steel, an aluminum alloy does not necessarily have a minimum strength based on the base material. Sometimes, the aluminum alloy can be much weaker than the alloy that is welded.
Clean the Aluminum Properly Before Welding
When cleaning the aluminum, always use a carbon steel brush to clean it rather than relying on a wire brush. The wire brush is simply not effective enough at cleaning the aluminum.
Use the Right Torch Settings
When welding aluminum with TIG welding, you will need to set the unit to high frequency and continuous. Otherwise, you will cause it to stall. You will often need to adjust this when working with aluminum. Avoid using a high torch angle because this can cause the filler metal to melt too much and can lead to the aluminum forming globs of aluminum, which will ruin the weld. You will waste aluminum and the weld will look terrible and likely not be as structurally sound.
Make sure you use the right sizes of electrodes when welding aluminum. Make sure the electrode is the right size because an electrode that is too small will cause the electrode to blow up. Also, make sure the filler rod size is large enough so that the filler rod does not melt before you can perform any welding. Also, make sure the rod is not so large that you block the shielding gas. If you do not have enough gas coverage, this will increase the risk of contamination, which can cause the aluminum weld to develop defects.