How many amps are required to weld 1/8" aluminum?

• A. 75
• B. 125
• C. 100
• D. 150

Answer: (B)

Choosing the right amperage controls heat input and penetration. Aluminum conducts heat quickly and has an oxide layer that must be cleaned and melted during welding, so you need enough current to melt the base metal and fuse it with the filler without overdoing it. For 1/8" aluminum, a mid-range setting around 125 amps is common and reliable with TIG welding. This level gives solid fusion and penetration without the excessive heat that can cause burn-through, distortion, or porosity. Using significantly less current (like 75 or 100 amps) risks poor fusion and a weak weld, while pushing up to 150 amps can overheat the joint and warp the material. Keep in mind exact numbers can vary with the welding process, joint type, filler, and machine, but 125 amps is a standard, safe target for this thickness.