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A question that many people new to welding ask is whether it’s possible to weld aluminum with AC TIG. New welders may also wonder why they would use alternating current to weld aluminum and if it’s possible to TIG weld aluminum using direct current. While it is possible to TIG weld aluminum with direct current, we’ll talk about alternating current while TIG welding aluminum.
Interesting Facts About Aluminum
Using aluminum for roofs makes the aluminum-coated roof more energy efficient since it reflects up to 95% of solar energy, lowering utility bills. Aluminum never rusts, but it is prone to corrosion once exposed to weathering. The Earth’s crust contains 8.2% aluminum, making it the most abundant metal, which is why it costs less than other metals.
Why Is Aluminum Difficult to Weld?
Many people find it difficult to weld with aluminum, and with good reason. Aluminum is a soft, thin, highly sensitive material that is easy to contaminate and insulated by an oxidized layer. It also has a low melting point and higher thermal conductivity, which means that welders have to be careful not to burn through the metal; otherwise, they hinder the quality of the material.
How to Weld Aluminum
Below are a few steps to take to weld aluminum and avoid imperfections and burn-through:
Avoid Contamination
It’s important to avoid environmental or atmospheric contamination when AC TIG welding aluminum. You must first adequately clean the aluminum piece and all of your materials to avoid porosity during the welding. To avoid atmospheric contamination, you must use hoses that are in good or new condition and prevent air from finding its way into the lines.
Use Correct Polarity and Output Frequency
Even though you’ve cleaned your materials, you should know that an oxide layer will start forming on them almost immediately. Since the oxide layer doesn’t waste time reforming, it’s important to use AC polarity when welding, as the alternating current helps break up the oxide layer. The higher the AC output frequency, the more stable and focused arc you’ll have.
Add Filler Metals
The goal of any weld when working with aluminum is to give it a smooth appearance that makes it look like a stack of dimes spread out as though you were counting them. Adding a filler metal to your weld makes achieving the stacked coin look more manageable, as it causes a cooling effect on the other side of the weld puddle. Two of the best filler metals are alloys 5356 and 4043, which account for up to 80% of welding projects that use aluminum.
Use Short Arcs
When working with aluminum, it’s essential to use a shorter arc to focus the heat during the welding process. When you have a short arc length, the electron’s motion speed is slower, but be careful not to make your arc so short that your electrode sticks to your base material.
Last Words
Taking these steps above can help transform your welding experiences. To the question “Can you weld aluminum with AC TIG?”, the answer is yes if you have the right equipment and ensure proper conditions are met.
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