One important rule for choosing proper amperage for TIG Welding Aluminum is to use 1 ampere for every thousandth (1/1000) of the aluminum thickness.
For example, to TIG weld an aluminum piece that is 1/8 inch in thickness would require 125 amperes.
However, as the thickness of the base material is higher, the above rule is no longer correct.
If you weld a 3/8 inch piece of aluminum, you only need a power source of 280 amperes (not 375 amperes, as per the rule).
Also, the amperage also depends on the type of joints.
For example, a T-joint would demand a higher power source than a Butt joint, because:
- In T-joint, heat can flow in three directions,
- While in the Butt joint, heat flows in two directions only.
To set the desired amperage, you can:
- Make use of a foot pedal or fingertip
- Rely on your TIG Welder by changing AC Balance (increasing EN), or setting AC amperage independently (if allowed by the machines).
Below is an Amperage Chart for your reference
| Aluminum Thickness | Tungsten Diameter | Filler Rod Diameter | Amperage for TIG Welding Aluminum |
| 0.010”- 0.035” | 0.040″ | 0.024″-0.030″ | 5- 25 |
| 0.035″- 1/8” | 1/6″ | 0.030″-0.045″ | 20-85 |
| 3/32″ – 1/4″ | 3/32″ | 1/16″ – 3/32” | 50 – 180 |
| 3/16″ – 3/8″ | 1/8″ | 3/32″ – 1/8″ | 171- 250 |
| 5/16″- 1/2” | 5/32″ | 1/8″ – 3/16″ | 200 – 320 |
