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Aluminum wire

STAHLWERK ER4043 (AlSi5) Ø 1.0 mm, 0.45 kg

Aluminum wire is soft, and that single fact governs everything about feeding it.

STAHLWERK ER4043 (AlSi5) Ø 1.0 mm, 0.45 kg, product photograph

STAHLWERK ER4043 (AlSi5) Ø 1.0 mm, 0.45 kg

Aluminum wire is soft, and that single fact governs everything about feeding it.

Grade
ER4043 (AlSi5)
Diameter
1.0 mm (0.04 in)
Weight
0.45 kg (1 lb)
Spool
D100, 16 mm (0.63 in) bore
Amazon reference
B0CQRLD4BF
EAN
4260746547467
  • ER4043 is the general-purpose aluminum filler, forgiving and crack-resistant
  • 1.0 mm (0.04 in) is the practical minimum for aluminum: thinner wire buckles even sooner
  • Soft wire birds-nests in a standard steel liner: a Teflon liner or spool gun is close to mandatory

Best for: Occasional aluminum work on a machine equipped for it

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Specifications

Grade
ER4043 (AlSi5)
Diameter
1.0 mm (0.04 in)
Weight
0.45 kg (1 lb)
Spool
D100, 16 mm (0.63 in) bore
Amazon reference
B0CQRLD4BF
EAN
4260746547467

ER4043 versus ER5356

Four-oh-four-three is silicon-alloyed: it flows well, tolerates a range of base alloys and resists cracking, which makes it the default for repair work. Five-three-five-six is magnesium-alloyed, stronger and stiffer — easier to feed, harder to get right. For general aluminum repairs, ER4043 is the safer choice.

Before you order

Check what your machine will do with it. A MIG machine without pulse and without a spool gun interface can be made to weld aluminum, badly, on short runs. If aluminum is a real requirement, the machine matters more than the wire.

Sources

Every figure above comes from the manufacturer’s published specification for this reference. Fields the listing does not publish are left out rather than estimated. Market availability was verified per market on the EAN.

The questions welders ask

Why can I not just load it like steel wire?

Because aluminum is soft. Steel wire is stiff enough to be pushed four meters down a liner; aluminum compresses and coils behind the drive rollers instead — the bird’s nest every first attempt produces. The fixes, in order of effectiveness: a spool gun with the spool in the handle, a Teflon or graphite liner with U-groove rollers, and a very short torch.

Why is the spool so small?

Because aluminum wire is used in short campaigns and degrades in storage — it oxidizes, and the surface layer is what causes feeding problems and porosity. Buying it in 0.45 kg lots means the wire you load is fresh, which matters more here than the price per kilogram.

Welders this fits

More mig wire

  • STAHLWERK ER70S-6 (SG2) Ø 0.8 mm, 2 × 5 kg, product photograph

    STAHLWERK ER70S-6 (SG2) Ø 0.8 mm, 2 × 5 kg

    The same wire as the single spool, twice — worth it only if you will use it before it corrodes.

    Grade
    ER70S-6 (SG2)
    Diameter
    0.8 mm (0.03 in)
    Quantity
    2 spools of 5 kg (11 lb)
    Amazon reference
    B0BZJSZFPP
    EAN
    4260746545807
    • Cheaper per kilogram than buying two single spools
    • Same grade and diameter as the single-spool version — no compromise for the discount
    • The second spool sits opened or unopened for months, and steel wire corrodes

    Best for: A workshop welding weekly, where the second spool will be used within months

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  • STAHLWERK ER70S-6 (SG2) Ø 0.8 mm, 5 kg, product photograph

    STAHLWERK ER70S-6 (SG2) Ø 0.8 mm, 5 kg

    The default steel MIG wire: 0.8 mm (0.03 in), ER70S-6, on a 200 mm (7.87 in) spool that most machines take.

    Grade
    ER70S-6 (SG2, G3Si1)
    Diameter
    0.8 mm (0.03 in)
    Weight
    5 kg (11 lb)
    Spool
    D200 — 200 mm (7.87 in) diameter
    Amazon reference
    B07TLNMGGW
    EAN
    4260294085152
    • ER70S-6 is the general-purpose steel grade: it tolerates mill scale and rust better than ER70S-3
    • 0.8 mm (0.03 in) suits 1–5 mm (0.04 to 0.20 in) steel, which is most workshop work
    • D200 spools do not fit the smallest portable machines, which take D100 only

    Best for: General steel welding on any machine that takes a 200 mm (7.87 in) spool

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  • STM Schweißtechnik SG2 (G3Si1) Ø 1.0 mm, product photograph

    STM Schweißtechnik SG2 (G3Si1) Ø 1.0 mm

    One millimeter wire: more deposit per pass on thick steel, and unusable on car-body sheet.

    Grade
    SG2 / G3Si1
    Diameter
    1.0 mm (0.04 in)
    Spools
    D100, D200 and K300 sizes offered
    Amazon reference
    B083KFWQ27
    EAN
    0670036746151
    • More metal deposited per pass — fewer passes on 6 mm (0.24 in) and above
    • Available on K300 spools for machines that take them
    • Needs more current: a 160 A machine will struggle to run it properly

    Best for: Structural work in 5 mm steel and above, on a machine of 180 A or more

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Elsewhere in the workroom

  • STARK Rutile all-round Ø 3 × 350 mm, 5 kg, product photograph

    STARK Rutile all-round Ø 3 × 350 mm, 5 kg

    A hundred and eighty-five rods in a box — the format for a project rather than a repair.

    Type
    Rutile, all-round
    Dimensions
    Ø 3 mm (0.12 in) × 350 mm (13.8 in)
    Quantity
    5 kg (11 lb), approximately 185 rods
    Amazon reference
    B01N07QIID
    EAN
    4402300500550
    • 185 rods: enough for a gate, a trailer repair or a season of practice
    • Rutile all-round, so it strikes easily and works in most positions
    • Even rutile rods absorb moisture — a 5 kg (11 lb) box needs dry storage

    Best for: A project with a lot of welding in it, at 5 mm (0.20 in) and above

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  • Hobart 308L stainless steel stick electrodes

    Hobart H481930-RDP, 308L stainless, 3/32 in

    The only stainless rods in this hub — on a listing whose four bullets are a product type, a parcel size, a country and a weight to six decimal places.

    Amazon reference
    B002AKJ23Y
    EAN
    0715959249836
    • The only stainless electrodes in this hub, either half
    • Names the base metals it is for — 304 and 308 stainless — rather than saying "stainless"
    • The four bullets contain no welding specification at all — product type, parcel dimensions, country of origin and parcel weight

    Best for: Repairing 304 or 308 stainless with a stick machine, where no MIG gas is available

    ≈ $11
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  • Hobart 6011 stick electrodes, 1/16 inch, in their one-pound pack

    Hobart H112216-R01, 6011, 1/16 in

    A deep-penetrating 6011 in the smallest diameter on this shelf, stated for welding through light to medium dirt, rust and paint.

    Amazon reference
    B004USV1RE
    EAN
    0715959286619
    • Stated for welding through light to medium dirt, rust and paint — the one job a clean-metal rod cannot do
    • Publishes a tensile strength: 60,000 PSI
    • A cellulosic coating gives a fierce, spattery arc — this is not a rod to learn on

    Best for: Farm and repair work on steel that cannot be cleaned first

    ≈ $16
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All mig wire