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4043 Aluminum MIG Welding Wire

Nexalloy
|
MW404303001
  • .030 inch (0.8mm) 1lbs.
  • .035 inch (0.9mm) 1lbs.
  • .045 inch (1.2mm) 1lbs.
  • .030 inch (0.8mm) 5lbs.
  • .035 inch (0.9mm) 5lbs.
  • .045 inch (1.2mm) 5lbs.
  • .035 inch (0.9mm) 16lbs.
  • .045 inch (1.2mm) 20lbs.
  • 1/16 inch (1.6mm) 20lbs.
$15.39 $0.00( / )
Shipping calculated at checkout.
QTY Discount
2+ 3%
10+ 5%
20+ 7%
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4043 Aluminum MIG Welding Wire

AWS CLASS
ER4043
PROCESS
MIG (GMAW)
BASE ALLOYS
6000 Series
SILICON
5%
DIAMETERS
.030"–1/16"

ER4043 Aluminum MIG Welding Wire known for versatility and forgiving nature. Excellent for welding 6000 series aluminum alloys. Silicon additions improve fluidity and produce smooth, clean welds with minimal spatter. Less prone to cracking.

Key Features

  • Versatile and forgiving — reliable for professionals and hobbyists
  • Excellent for 6000 series aluminum alloys
  • Silicon additions improve fluidity and reduce spatter
  • Smooth, aesthetically pleasing welds less prone to cracking
  • Available in multiple diameters and spool weights

Technical Specifications

AWS ClassificationER4043
Welding ProcessMIG (GMAW)
Base Alloys6000 series aluminum
Silicon Content5%
Available Diameters.030", .035", .045", 3/64", 1/16"
Available Spool Weights1 lb, 5 lb, 16 lb, 20 lb

Part Number & Size Reference

MW404303001 — 0.030" / 1 lb spool
MW404303501 — 0.035" / 1 lb spool
MW404304501 — 0.045" / 1 lb spool
MW404303005 — 0.030" / 5 lb spool
MW404303505 — 0.035" / 5 lb spool
MW404304505 — 0.045" / 5 lb spool
MW404303516 — 0.035" / 16 lb spool
MW404336420 — 3/64" / 20 lb spool
MW404311620 — 1/16" / 20 lb spool

Related Products

5356 Aluminum MIG Welding Wire | 5554 Aluminum MIG Welding Wire | 5356 Aluminum TIG Rods 10lbs. | 4043 Aluminum TIG Rods 10lbs. | 5554 Aluminum TIG Rods 10lbs. | 4043 Aluminum Stick Electrodes 5lb

Frequently Asked Questions

ER4043 is a silicon-alloyed MIG wire built for welding 6000 series aluminum. The 5% silicon addition makes the puddle flow more easily, which is why it's often the default recommendation for general aluminum fabrication.

It's formulated for 6xxx series base metals — alloys like 6061 and 6063 that are common in extrusions, frames, and structural aluminum.

The silicon lowers the melting point and improves fluidity of the weld puddle, giving you a smoother-looking bead with less spatter and a lower chance of cracking than some alternative fillers.

You can get it in .030", .035", .045", 3/64", or 1/16", matching the sizing most MIG guns and spool guns are set up for.

It's stocked in 1 lb, 5 lb, 16 lb, and 20 lb spools, so you're not stuck buying a bulk spool for a one-off repair or constantly rebuying small ones for a bigger job.

Generally, yes. Its smoother-flowing puddle and lower spatter make it more forgiving to run than some other aluminum fillers, which is part of why it's a common recommendation for less experienced welders.

Its silicon content does make it less crack-sensitive than straight aluminum or some magnesium-alloyed fillers, which is one reason it's the standard choice for general-purpose 6xxx welding.

Yes — 6xxx series alloys, which cover most common aluminum extrusions and structural framing, are exactly what 4043 is designed to match.

For 6061 and other 6xxx alloys, 4043 is the standard match. 5356 is intended for 5xxx (magnesium) base metals, so using it on 6061 wouldn't give you the same fluidity or crack resistance that 4043's silicon content provides.

The improved fluidity from the silicon addition tends to produce a flatter, smoother bead profile with less spatter clean-up needed, which is part of why it's popular for visible or cosmetic aluminum welds.