ER4043 vs ER5356 Welding Wire: Which is Best for Your Aluminum Welding Needs?

If you're in the market for aluminum welding wire, you've likely come across ER4043 and ER5356—two of the most commonly used filler metals. But which one is right for your application? 

1. Chemical Composition: How They Differ
The primary difference between ER4043 and ER5356 lies in their alloy composition:

ER4043
Silicon (Si): 5%
Aluminum (Al): Balance
Magnesium (Mg): Trace amounts
Best for high-temperature applications due to silicon's fluidity.

ER5356
Magnesium (Mg): 5%
Aluminum (Al): Balance
Silicon (Si): Minimal
Offers higher strength and corrosion resistance in marine environments.

2. Strength & Durability Comparison
ER5356 provides greater tensile strength (around 40,000 psi) compared to ER4043 (around 30,000 psi).
ER4043 is more crack-resistant when welding heat-treated aluminum alloys (like 6061).
ER5356 is preferred for structural and load-bearing welds due to its higher strength.

3. Best Applications for Each Wire

4. Welding Performance & Ease of Use
ER4043 flows better, making it easier for beginners and suitable for thin materials.
ER5356 requires more skill but produces cleaner, stronger welds on thicker aluminum.
Anodizing Compatibility: ER5356 welds anodize better, while ER4043 may turn dark gray.

5. Pricing & Availability for Bulk Buyers
ER4043 is generally more affordable and widely available.
ER5356 may cost slightly more due to its magnesium content, but offers better long-term durability.
Wholesale Tip: If your customers weld marine or structural aluminum, stock more ER5356. For general fabrication, ER4043 is a cost-effective choice.

Final Recommendation for Buyers
Choose ER4043 if you need:
Smooth welds on cast or heat-treated aluminum.
Lower cost for non-structural applications.

Choose ER5356 if you need:
High strength and corrosion resistance.
Welds that will be anodized or exposed to saltwater.