ER5356 aluminum filler

Hobart favors 5356 for anodized color match but advises against it for long-term exposure above 150°F (about 65.6°C). Its guidance discusses 5454 base alloy with ER5554 for elevated-temperature use and 4043 for compatible lower-magnesium alloys. Qualify the alloy pair, service duration and finish rather than substituting on appearance alone. Hobart Brothers, Elevated-temperature applications Hobart Brothers, Filler-selection guidance

ESAB contrasts the approximately 5% magnesium in ER5356 with approximately 5% silicon in 4043. Check the exact base alloys, tempers and service. ESAB, How to choose between 4043 and 5356 filler alloy, September 26, 2024

Classification and product identity

Hobart's MaxalMig/MaxalTig 5356 datasheet, printed revision 250114 replacing 241216, lists AWS A5.10 ER5356 and R5356, with magnesium 4.5–5.5% and aluminum as the remainder. The alloy number identifies a chemistry family, not a tensile-strength code. Preserve the product form and diameter: spooled GMAW wire and cut-length GTAW rods require different feeding and process arrangements. Confirm the required AWS edition and current conformity documentation. Hobart Brothers, Maxal 5356 datasheet

A bounded purchasing example is MaxalTig 5356 part 535609470, a 3/32 in (2.4 mm) GTAW filler in a 10 lb carton. Its product page lists classification, agency approvals and package sizes separately. That identifies a consumable; it does not certify an unknown loose rod, a welded assembly or an application beyond the approval's actual scope. Keep package and lot identity available through use. Hobart Brothers, MaxalTig 5356 product details

Select for the base alloy and required properties

Hobart's filler-selection guidance permits 4043/4943 or 5356 for many 6xxx alloys and for 5xxx alloys containing up to 2.5% nominal magnesium, subject to the application. For 5xxx alloys above that magnesium level it recommends 5356 and excludes 4043/4943. This is a manufacturer's family-level guide; use the actual alloy-pair chart and procedure requirements rather than assuming every member of a series behaves identically. Hobart Brothers, Selecting 4043/4943 or 5356

When both filler families are permitted, the choice still changes behavior. ESAB identifies greater ductility and shear strength with 5356, while 4043 generally offers smoother wetting, less smut and lower cracking sensitivity. It identifies 6061 as one common base alloy for which either may be appropriate. Do not convert that example into approval for every 6061 joint, temper or service condition; joint design and required properties remain part of selection. ESAB, 4043 versus 5356

Anodizing is another selection criterion. Hobart recommends 5356 for a good anodized color match, while ESAB notes that 4043 commonly turns dark gray. A closer match is a comparative benefit, not a promise that a weld will be invisible after every anodizing treatment. Agree the finish requirement and representative sample before relying on appearance alone. Hobart Brothers, Filler-selection guidance; ESAB, 4043 versus 5356

Sustained elevated temperature is a selection limit

Hobart’s elevated-temperature guide explains that prolonged exposure in the 150–350°F range can form grain-boundary precipitates in aluminum–magnesium alloys above about 3% magnesium and increase susceptibility to stress-corrosion cracking. Apply the limit to sustained service exposure. Set welding and preheat temperatures separately. Hobart Brothers, Elevated-temperature applications

A different filler must also suit the base metal. The guide identifies 5454 base alloy with ER5554 filler as a deliberately lower-magnesium combination for elevated-temperature applications, and discusses 4043 for compatible lower-magnesium base alloys. These examples do not authorize 4043 on high-magnesium 5xxx joints. Review the complete assembly and exposure history. Hobart Brothers, Elevated-temperature applications

Typical filler strength is not welded-component strength

The cited Maxal datasheet reports 40 ksi typical tensile strength, alongside 35 ksi in its AWS-specification column, and explicitly bounds its typical results to the test procedure. That does not establish a production joint's allowable stress or restore a heat-treated base metal's original temper. Hobart Brothers, Maxal 5356 datasheet

Hobart's metallurgy guide distinguishes heat-treated 6xxx alloys from strain-hardened 5xxx alloys. Welding can degrade the 6xxx heat-affected-zone microstructure and remove the cold-work strengthening contribution from 5xxx material near the weld. Strength assessment must therefore include filler, fusion zone, HAZ, original temper and any specified postweld treatment. Choosing a higher-strength filler alone does not establish the weakest region of the finished joint. Hobart Brothers, Heat-treatable and non-heat-treatable alloys

Process and wire delivery

For its 5356 product, Hobart lists DCEP for GMAW and AC for GTAW, with argon or argon/helium shielding. Apply the welding procedure specification (WPS), machine instructions and actual diameter data; the alloy classification does not specify a single amperage, pulse program or gas-flow setting. Hobart Brothers, Maxal 5356 datasheet

Aluminum wire is softer and harder to feed than steel. Miller describes spool-gun and push-pull arrangements as ways to improve aluminum-wire delivery; a push-pull system coordinates a pulling gun motor with feeder assistance. Use the compatible liner, gun and drive system instead of assuming a steel-wire setup will feed 5356 reliably. Spray and pulsed-spray processes also differ in heat input and out-of-position behavior, so changing transfer mode requires checking the procedure rather than merely preserving wire-feed speed. Miller, Aluminum welding systems and filler metal

Cleanliness, storage and diagnosis

Store filler dry and protected from temperature swings and condensation. Hobart's preparation guide recommends bringing filler and base material into the welding area 24 hours before use to acclimate, keeping wire covered, and cleaning the joint before assembly. It specifies degreasing before stainless-steel brushing so brushing does not embed hydrocarbons. Treat that acclimation period as manufacturer guidance, not proof that every package or environment is automatically dry after a fixed time. Hobart Brothers, Metal storage and joint preparation

Black smut is not by itself proof of the wrong filler. Hobart explains that magnesium in 5xxx filler vaporizes and condenses around the bead, while air, moisture and other contamination can increase oxidation and discoloration. Check shielding coverage, drafts, gas delivery and cleanliness before changing alloy. Cosmetic improvement must remain compatible with the original material and service requirements. Hobart Brothers, Weld discoloration, spatter and black smut

The North American MaxalMig/MaxalTig 5356 SDS, version 1.0, revised January 8, 2026, addresses the actual wire and rods. It warns that welding creates fume, radiation and electric-shock hazards despite the solid product's as-shipped classification. Use ventilation/local exhaust, appropriate eye/skin protection and operation-specific exposure assessment. Prevent dust generation during cleanup and follow the supplied product's handling and disposal instructions. Hobart Brothers, 5356 SDS

Related references

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