ER4043 Aluminum Wire: MIG & TIG Amperage, Settings & Alloy Guide

The general-purpose aluminum MIG and TIG wire. Runs 50 to 250 amps on DCEP or AC, rated for flat, horizontal, vertical up, overhead. Amperage chart by diameter below.

ER4043 is a silicon-alloyed aluminum filler wire used for MIG and TIG welding on most common aluminum alloys. The 5% silicon content lowers the melting point and improves fluidity, which means fewer hot cracks, easier bead starts, and smoother weld puddle control. It welds 1xxx, 3xxx, and 6xxx series aluminum alloys. The weld color will not match anodized base metal because the silicon content changes the surface appearance after anodizing. For general fabrication, repair work, automotive, marine, and most shop applications on 6061 or cast aluminum, ER4043 is the default wire. It forgives more operator error than ER5356.

What This Means in Practice

ER4043 means: ER (electrode rod for MIG/TIG) + 4043 (Aluminum Association alloy 4043, which is an Al-5%Si alloy). The 4xxx series aluminum alloys are silicon-alloyed, designed specifically as filler metals.

What Amps for ER4043?

What Is ER4043 Good For?

6061, 6063, 3003, and cast aluminum welding (MIG or TIG).

Automotive and marine aluminum repair.

General fabrication where anodized color match does not matter.

Brazing-like applications on thin aluminum.

Any situation where crack resistance is the priority.

Where ER4043 Falls Short

Not for 5xxx series aluminum (5052, 5083, 5086), use ER5356 instead.

Weld beads will not match anodized color due to silicon content.

Lower shear strength in fillet welds compared to ER5356.

Not recommended where the weld will be exposed to sustained temperatures above 150 deg F (the dissimilar silicon creates a lower-melting eutectic).

Welding With ER4043

What You Hear and See

Soft, smooth arc on TIG with AC. The 5% silicon content lowers the melting point and makes the filler flow easily into the puddle. On MIG with a spool gun, the arc crackles lightly.

Running It

TIG: feed the rod into the leading edge of the puddle at a shallow angle. Dab in a consistent rhythm. Use a foot pedal to control heat. MIG: push at 10-15 degrees with a spool gun or push-pull system.

Puddle and Slag

Very fluid, shiny puddle that wets out easily on aluminum. The silicon content reduces cracking tendency and improves fluidity. The bead has a bright, almost mirror-like finish on clean aluminum.

If You Are Struggling

If the filler balls up instead of flowing into the puddle, the base metal is not hot enough. Increase amperage or wait for the puddle to form before dipping. If you see black soot, your tungsten is contaminated. Regrind it.

ER4043 Size by Material Thickness

Shop Talk

ER4043 is the default aluminum filler rod. It works on the most common aluminum alloys: 6061, 6063, 3003, and casting alloys. The silicon content gives it hot crack resistance that ER5356 does not have on silicon-bearing base metals. The trade-off is lower shear strength than ER5356 and a darker color after anodizing. For most aluminum TIG work, ER4043 is the starting point.

Common Brand Names for ER4043

Look for Lincoln Electric SuperGlaze 4043 at your supplier. 3 companies produce ER4043-classified rods.

Data sourced from AWS A5.10/A5.10M. Amperage ranges are approximate starting points. adjust based on position, fit-up, and material thickness. Always follow manufacturer recommendations and applicable codes.