Wire hardness

What factors influence a wire's resistance to torsion?

Beyond a metal’s position on the hardness scale, two other factors come into play regarding its ability to withstand torsion:

• The wire’s temper: the same metal behaves differently depending on whether it is annealed, medium-hard, or hard.
• Diameter: A thin wire always yields faster than a thick wire made of the same metal.

Annealed, semi-hard, hard: which temper is best for which application?

Hardness refers to the state of a wire, regardless of the metal it is made of:

• Annealed (soft): easy to shape by hand, ideal for curves and coiling, but weakens more quickly if you twist it multiple times in the same spot.
• Medium-hard: a compromise between flexibility and strength, often used in wire wrapping.
• Hard (work-hardened): holds its shape perfectly and resists repeated twisting better, though it requires more skill to work with.

Semi-hard 925 Sterling Silver wire, for example, does not hold up well when twisted around itself multiple times into a small diameter: it becomes brittle and breaks. The same metal in a hard version and with a thicker diameter (about 1 mm for studs or rings) will hold up much better.

From softest to hardest: the metal hardness scale

Note that the hardness scale is provided for reference only, and that the wire’s temper and diameter also influence its level of strength.

Unsurprisingly, not all metal wires perform equally well under repeated twisting. From the most flexible to the hardest:

• Copper is the softest metal in the range; it’s pleasant to work with but should be reserved for pieces that aren’t subjected to intense, repeated twisting.
• Bronze, just above it on the scale, offers slightly better strength than copper while remaining easy to work with.
• Brass is closer to the hard end of the scale, making it a reliable choice for wire wrapping.
• 925 Sterling Silver falls in the middle of the scale: in its semi-hard form, it does not withstand repeated twisting well and tends to become brittle, especially at small diameters; in its hard form, it gains significantly in strength.
• Gold Filled, which is one notch harder than brass, is still best chosen in its hard form and with a thick diameter (1 mm or greater) for rigid pieces such as studs, rings, or earstuds.
• Stainless steel is the hardest metal in the range: it’s ideal for pieces that need to maintain a precise shape, but requires more force to work with. It’s also recommended to use pliers designed for this metal to avoid damaging your tools.

(Note: Aluminum does not appear on this scale, as it is too soft and malleable to be compared to the other metals based on this criterion.)

Our tips for preventing breakage

• Avoid bending and unbending the wire repeatedly in the same spot.
• Use appropriate pliers rather than your fingers for tight twists.
• If a wire consistently breaks at the same point, switch to a larger diameter before changing metals.
• If you’re unsure about diameters, our gauge-to-mm conversion chart will help you figure it out.