40433641C - Nexalloy ER4043 Aluminum MIG Wire 3/64 (0.045) 1lb Spool

Premium ER4043 Aluminum MIG Wire for General Fabrication

The Nexalloy 4043 Aluminum MIG Wire is a high-quality, general-purpose welding wire designed for joining heat-treatable base alloys. Specifically formulated with a 5% silicon content (AlSi5), this wire is the industry standard for welding 6XXX series alloys, such as the widely used 6061-T6. The addition of silicon significantly lowers the melting point of the filler metal, increasing fluidity and improving the wetting action of the weld pool. This characteristic makes ER4043 exceptionally user-friendly, producing a smooth, flat, and bright weld bead that requires minimal post-weld cleaning.

One of the primary advantages of Nexalloy 4043 is its reduced sensitivity to weld cracking. Aluminum alloys in the 6XXX series are known to be hot-short (prone to cracking at high temperatures), but the chemistry of the 4043 filler helps bridge the solidification temperature range, mitigating this issue. This makes it an excellent choice for automotive components, bicycle frames, trailers, and general industrial repairs where structural integrity and leak-proof joints are critical.

This 1 lb spool is perfectly sized for use with spool guns, which are commonly attached to standard MIG welding machines to prevent the feeding issues associated with soft aluminum wires in long liners. The 3/64" (often cross-referenced as 0.045") diameter provides a versatile deposition rate suitable for medium-to-thick base materials. While 4043 is not recommended for parts that will be anodized for color match (as it turns dark gray), it is the go-to alloy for the vast majority of general aluminum welding applications requiring ease of use and reliable mechanical properties.

Key Applications

• Automotive parts and engine components


• Bicycle frames and recreational equipment


• Truck bodies and trailers


• General fabrication of 6061 and 6063 aluminum


• Repair of cast aluminum parts (356.0)