Are you looking for the right TIG filler wire to weld aluminum, mild steel, or stainless steel? In this article, we’ll break down the best wire for each material and highlight their benefits.

Aluminum Filler Wires

• ER4043 – The most versatile and commonly used aluminum filler. Provides a smooth, clean weld and is ideal for general fabrication.

• ER5356 – Stronger than 4043 with excellent corrosion resistance, especially in marine or chemical environments. Weld pool is less fluid but offers greater durability.

• ER4943 – A modified 4043 wire designed for 6xxx series aluminum when higher tensile strength is required.

Mild Steel Filler Wires

• ER70S-2 – A versatile choice for most job shops. Contains triple deoxidizers (Al, Ti, Zr) to handle surfaces with mill scale, rust, or oil, producing smooth, clean welds every time.

• ER70S-6 – Best for clean material. With higher levels of manganese and silicon, it creates a stiffer weld pool, making it well-suited for out-of-position welding.

• ER80S-D2 – Designed for high-strength, low-alloy steels where extra toughness and durability are needed, such as structural and heavy equipment applications.

Stainless Steel Filler Wires

• ER308L – The most common stainless filler, used for welding 304 stainless. Its low carbon content provides excellent corrosion resistance, making it ideal for general use and food-grade applications.

• ER309L – Suitable for welding dissimilar stainless steels or stainless to carbon steel. Offers higher crack resistance and durability than 308L.

• ER316L – Provides superior resistance to chlorides, making it the top choice for marine, chemical plant, and harsh cleaning environments.