TIG Welding Aluminum: Tips & Techniques | How to Weld?

TIG welding aluminum is a challenging process but not that difficult as long as you remember a few basics. Do you know why most manufacturers prefer to use aluminum? Because the products that are manufactured with aluminum can increase the product life, reduce the weight, and resist elements at a cold temperature. These products can be trailers, trucks, piping, and other material. 

Aluminum TIG welding demands a shielding gas, a non-consumable tungsten electrode, and a clear metal surface to eliminate the oxide formation. Remember, oxide has a higher melting point than aluminum, so it’s a good practice to remove it before welding. Aluminum welding is full of challenges, and some of them are mentioned below along with the tips to overcome them. 

Aluminum TIG Welding

GTAW Aluminum Welding Challenges

Controlling the heat input is the biggest concern in welding and it’s even tougher when you want to achieve high-quality results. Clearly, tungsten inert gas welding is a slow process and it takes time to gain a complete grasp of it. You also need the perfect aluminum welding machines and you can check these best aluminum tig welders from here.

As mentioned above, proper heat input and control are the key points of aluminum welding. As aluminum is a conductive metal, we can quickly remove the weld puddle heat.  A huge amount of heat must be applied to create the weld puddle. But you need to control the heat otherwise excessive puddles can be created. 

Many folks ask how to TIG weld aluminum and we have shared the tips and techniques to control the heat to optimize weld results. 

Use the Correct Polarity

Polarity is the main point in welding but before it, one must be aware of oxidation. You should have the knowledge of whether this metal generates the oxide layer or not. We can’t see the oxidation on aluminum because of its dull silver color. That’s why it’s recommended to clean and rub the metal to remove the oxide layer. 

Did you know that aluminum oxide melting point is three times more than melting temperature of base metal?

Sometimes, after much cleaning the oxide layer reforms quickly. You may think what’s the solution to this? Use the AC polarity because it provides a cleaning action that completely eliminates the oxide layer on aluminum which portrays the clear molten weld pool. 

Set the Balance Control

Balance control is an important consideration when aluminum welding. During welding in AC polarity, there are two electrodes, electrode negative ( EN ), and electrode positive ( EP ) on the cycle. EP is considered for the oxide removal or cleaning whereas EN is the AC waveform of the welding side. 

The latest welding units offer the users to set the ratio according to the weld puddle situation. An issue arises here is that old welding machines have a built-in ratio of 50-50 for both EN and EP. Whereas, today’s machines have preset balance control of 25% EP and 75% EN. If there are small black dots in a weld puddle during welding, it means that balance control is not properly.  The term ‘peppering’ is used for these black dots. 

More EP and less EN assist to eliminate oxide and also reduce the peppering. Less electrode negative offers more cleaning and it’s mandatory when the material was not properly cleaned before welding. Remember the point that more EP or low EN applies most of the heat on tungsten which sometimes affects the tungsten tip. You can’t control the arc direction if the tungsten tip is affected. 

Use Correct Amperage 

In GTAW welding, the foot pedal is used to control the amperes. It’s our suggestion to set the maximum range on the equipment. A rule of thumb will help you out that use 1 ampere for one-thousandth (0.001), which means that if the base metal is (0.120) inch thick, you’ll need 120 amperes for it. 

Is it applicable to all?

It may vary based on different scenarios. T shape metal needs more heat and amperage because heat flows in three different directions.

Adjust the AC Output Frequency

Don’t confuse with the high-frequency arc start because it is only to initiate the arc. The output frequency means how many times per second an electrical power source switches the polarity. The stable arc is directly proportional to the higher ac output frequency that results in a precise arc in a proper direction, which allows you to weld accurately in tight locations. 

A wide arc cone forms between 80 and 90 Hz. On thin metals, set the frequency between 150-250 Hz to avoid burning of metal and precise welding on thin pieces. A low AC frequency between 80-120 Hz is good for welding thick metal pieces. 

Adjust the AC Amperage Independently

Everyone needs penetration and productivity in welding. AC amperage is a feature that helps you to achieve great penetration and creativity. This spec allows welders to get the best results during the weld. In short, adjusting the AC amperage independently provides you with more penetration to get the best bead and quality welds. 

Use Filler Rod 

tig filler rod for aluminum

Filler metal is evolved into a molten liquid and changes the metal state. Filler rods cool down the weld puddle which produces the beautiful and amazing appearance of the weld. The more filler rod, the more catchy look. Although filler metals are not necessary for this. You can also use foot pedal to get these looks. There are many techniques that only need a skilled person. 

Safety Should Be Priority

Safety should be your first concern because TIG welding aluminum produces a great amount of heat which can damage your skin. So, tig welding helmets, jackets, glasses, boots, gloves, and jackets are mandatory before starting the welding. You may check these boots and gloves for TIG welding. Try to use the new technology for your safety whether it’s a glove or auto-darkening helmets. 

Advantages & Disadvantages of TIG Aluminum Welding

What We Like
  • Usage of AC polarity
  • Top Quality welds
  • Can be done in tight positions
  • Best for thin metal pieces
  • Without slag & spatter
  • Attractive beads with filler rod
What We Don’t Like
  • Slow process
  • Not for outdoor tasks
  • Clean metal is necessary 
  • Demands high level skills

Frequently Asked Questions

Q. How can we avoid the runaway puddle?

Welding with a longer arc increases the voltage that produces excessive heat, which affects the whole metal. This heat quickly creates a runaway puddle. The best solution for this is to use a short arc length which will reduce the heat to a specific area rather than expanding on complete metal. 

Q. What is the best AC output frequency range for thin metals?

The frequency range between 150-250 Hz is ideal because it helps to achieve good results and also prevents the base metal from burning. 

Q. Which gas is used for aluminum tig welding?

Shielding gas ( argon ) is mostly used for aluminum welding as it keeps the weld pool safe from atmospheric contaminants. 

Q. Is there any alternative to aluminum tig welding?

In recent years, new technology is launched that allows the welding with brazing rods. 

Conclusion

TIG welding aluminum is a bit challenging task but with the right strategies and proper techniques, it’s much easier and simple. You need to remember some of the basic principles that are essential for GTAW. All of the major tips are explained according to our experience which has helped us to summarize the vast topic in a precise way.

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