FAA Aviation Mechanic General (AMG)Materials, Hardware and ProcessesMedium
A mechanic is TIG welding a repair on a 6061-T6 aluminum fuel tank baffle. Which filler rod is most commonly selected for this application?
- AE6010
- BERNiCr-3
- CER4043
- DER70S-6
Show answer & explanationAnswer & explanation
Correct answer: C. ER4043
ER4043 is an aluminum-silicon filler alloy widely used for TIG/gas welding aluminum structures because it produces sound, crack-resistant welds with good flow characteristics on common aluminum alloys like 6061.
Why the other options are wrong
- A. E6010 is a steel arc-welding electrode, unsuitable for aluminum.
- B. ERNiCr-3 is a nickel-based filler used for high-temperature nickel alloy welding, not aluminum.
- D. ER70S-6 is a carbon steel filler rod, not compatible with aluminum welding.
Aluminum Welding Filler Rod (4043)
An aluminum-silicon alloy filler rod commonly used for TIG/gas welding of aluminum aircraft structures due to good flow and crack resistance.
- 4043 contains ~5% silicon for better fluidity
- Reduces weld cracking compared to pure aluminum rod
- Widely used on 6061 and similar aluminum alloys
- Steel and nickel rods are not compatible with aluminum base metal
Memory trick: "Forty-forty-three flows free for aluminum repairs."