The most common failure in aluminum welding is not the welder’s technique — it is the wrong filler wire. Cracking, insufficient strength and color mismatch after anodizing can usually be traced back to a filler that does not match the base metal. This guide from Mastership (sole authorized distributor of Canadian Indalco aluminum welding consumables in Asia) explains how to choose between the five mainstream grades: ER4043, ER4047, ER5183, ER5356 and ER5554.
Step one: is your base metal a 4xxx or a 5xxx job?
Aluminum filler metals fall into two families. 4xxx (Al-Si) flows well and resists hot cracking — the right choice for castings and 6xxx-series base metals. 5xxx (Al-Mg) offers higher strength and better corrosion resistance — the right choice for structural work and marine applications. Confirm your base alloy first, then use the table below.
Five mainstream aluminum filler wires at a glance
| Grade | Alloy family | Base metals | Characteristics | Typical applications |
|---|---|---|---|---|
| ER4043 | Al-Si (approx. 5% Si) | 6061, 6063, aluminum castings | Excellent fluidity, crack resistant, smooth beads | Automotive components, general fabrication |
| ER4047 | Al-Si (approx. 12% Si) | Thin sheet, parts needing a low melting point | Low melting point, fast solidification, good gas tightness | Radiators, heat exchangers, brazing |
| ER5356 | Al-Mg (approx. 5% Mg) | 5xxx / 6xxx structural work | Most versatile; balanced strength and corrosion resistance; good anodized color match | Structures, bicycle frames, marine |
| ER5183 | Al-Mg (Mg comparable to 5356; Mn 0.5–1.0%) | 5083 and other high-strength base metals | Manganese addition gives the highest as-welded strength; the mainstay grade for class approvals | Shipbuilding, offshore, high-strength structures |
| ER5554 | Al-Mg (approx. 2.7% Mg) | 5454 base metal | Withstands sustained service above 65 °C; resists stress-corrosion cracking | Road tankers, chemical tank trailers, elevated-temperature parts |
The three questions we are asked most
For 6061 base metal — ER4043 or ER5356?
Either works; it depends on your priority. Choose ER5356 when you need strength and a consistent color match after anodizing. Choose ER4043 when you need crack resistance and puddle fluidity — for example casting repair or complex joints.
Which filler for marine aluminum?
5083 base metal with ER5183 is the standard combination for classification society work; general 5xxx structures and outfitting can use ER5356. What matters most is that the consumable carries class approval — the Indalco wire supplied by Mastership is approved by ABS, DNV, LR, BV and CCS, and certificates can be provided. See our guide to marine welding certification.
What about parts that run hot in service?
For sustained service above 65 °C (road tankers, chemical tank trailers), choose ER5554 among the 5xxx fillers. High-magnesium wires such as ER5356 and ER5183 are susceptible to stress-corrosion cracking (SCC) at elevated temperature.
Choosing the right wire also means choosing the right supplier
Mastership is the sole authorized distributor of Canadian Indalco aluminum welding consumables in Asia. We stock every grade in both MIG spools and TIG rods, and supply original datasheets, mill test certificates and hands-on selection advice. Not sure which grade you need? Contact us with your base alloy and application — we will recommend a grade and send samples.
Mastership | Aluminum Welding Consumables