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Solid wire · thick section

STM Schweißtechnik SG2 (G3Si1) Ø 1.0 mm

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

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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Specifications

Grade
SG2 / G3Si1
Diameter
1.0 mm (0.04 in)
Spools
D100, D200 and K300 sizes offered
Amazon reference
B083KFWQ27
EAN
0670036746151

One size does not cover the range

Wire diameter sets the useful current band. Keeping 0.8 mm (0.03 in) as the default and 1.0 mm (0.04 in) for thick jobs is how most workshops run — and swapping takes five minutes once the tips and rollers are to hand.

Check the spool size on offer

This wire is sold in several spool formats including K300, which is a large industrial size that most hobby machines cannot house. Match the spool to the machine before ordering, not after.

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

When is 1.0 mm (0.04 in) actually better?

When the steel is thick enough to absorb the heat. Larger wire carries more current and lays more metal per pass, so a 6 mm (0.24 in) fillet that takes three passes with 0.8 mm (0.03 in) may take two with 1.0. Below about 4 mm (0.16 in) the extra current has nowhere to go and you burn through — which is why most workshops keep 0.8 mm (0.03 in) loaded and change up for heavy jobs.

Do I need to change anything else?

Yes, two things: the drive roller groove and the contact tip, both of which are diameter-specific. Running 1.0 mm (0.04 in) wire through a 0.8 mm (0.03 in) tip jams; running it under a 0.8 mm (0.03 in) roller groove crushes it and feeds erratically. Both parts are inexpensive and both are commonly forgotten.

Welders this fits

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    Grade
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    Spool
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    Amazon reference
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All mig wire

Prices quoted in these summaries are dated readings. The live price is shown next to each product.