EX404300000047-M00 - ER4043 Aluminum MIG Wire - 0.047 in (1.2mm) - General Purpose Silicon Alloy

Smooth Running 4043 Aluminum MIG Wire (3/64")

If you are welding 6061 or other 6-series aluminum, this ER4043 wire in 0.047" (3/64") diameter is likely your best friend in the shop. Known for its "forgiving" nature, 4043 is an aluminum-silicon alloy that wets out beautifully, giving you that flat, smooth bead profile that looks great without much post-weld grinding. The added silicon lowers the melting point of the filler metal relative to the base metal, which helps the puddle flow smoothly and fill gaps easier than magnesium-based alloys like 5356.

One of the biggest headaches with aluminum MIG welding is hot cracking (centerline cracking) as the weld cools. This 4043 wire is specifically formulated to resist that cracking, making it a safer bet for rigid structures or complex joints. It runs on DCEP polarity and requires 100% Argon shielding gas (or an Argon/Helium mix for thicker sections). Because it is softer than 5356, you'll want to make sure your drive rolls are U-groove and your liner is Teflon or plastic to prevent shaving the wire, although 3/64" is stiff enough to feed reasonably well in proper setups.

Keep in mind that while 4043 welds look fantastic and are less prone to cracking, they will turn a dark gray if you try to anodize them later. If color-matching anodizing is critical, you might need 5356. However, for general fabrication, brackets, tanks, and repairs where ease of welding and bead appearance are priority #1, this 4043 wire is the industry standard.

Why Welders Choose 4043

• Great Flow: The puddle is fluid and easy to manipulate.
• Less Cracking: Silicon content helps prevent solidification cracks.
• Shiny Beads: Leaves a bright, clean finish with minimal smut.
• Versatile: Bonds well to most common aluminum grades (3003, 5052, 6061).