Jewelry Wire Gauge - Wire Hardness

Wire Hardness

All metals have a property called hardness. Hardness is the property of the metal that resists bending. Soft metals are pliable and easy to bend. Hard metals are stiff and hard to bend. The hardness of metals can be changed by heat treating the metal in a process called annealing or by simply bending the wire in a process called work hardening.

Wire, like all metals, will have this same hardness property. Most modern manufacturers of jewelry wire will make the wire with a defined hardness, generally labeled as a hardness of 0, 1, 2, 3, or 4. Historically, these numbers were associated with the number of times that the wire was pulled through the draw plate. The wire becomes harder or stiffer after each time it is drawn through the drawplate. A hardness of 0 meant that the wire was drawn only one time and was as soft and pliable as possible. A hardness of 4 meant that the wire was drawn five or more times and the wire was as stiff and hard as possible. Currently the designations 0, 1, 2, 3, and 4 no longer correlate to the number of times that the wire was drawn because the hardness of the wire can be changed by heat treating the wire. Practically, most jewelry wire is sold now as either dead soft, half-hard, or hard, with dead soft being wire manufactured with a hardness of 0, half-hard being wire manufactured with a hardness of 2, and fully hardened wire being wire with a hardness of 4.

Dead soft wire is extremely soft and pliable. It can be easily bent and is excellent for making rounded shapes including a spiral. The disadvantage of using soft wire is that the finished piece can be bent out of shape if not properly handled.

Half-hard wire is slightly stiffer than dead soft wire. Half-hard wire is excellent for making tight, angular bends, for making loops in wire, and for wrapping wire around itself. Finished pieces made with half-hard wire are often more permanent than pieces made with soft wire. Half-hard wire does not do a good job of making spirals.

Hard wire is very stiff and tends to spring back after being bent. This can make it harder to work with when using a jig. Hard wire will not make a spiral. The advantage to hard wire is that the wire components made out of hard wire are difficult to make but very permanent.

As in many things, no single wire is perfect for all applications. Soft wire is easy to bend and shape, but the finished product may be bent out of shape if squeezed. Hard wire is difficult to bend, but makes very permanent shapes. Half-hard wire is a compromise between the two. The ideal wire will be easy to bend, until in its final shape, but then very stiff. Obviously this ideal wire does not exist, so when making wire wrapped jewelry the wire is often hardened as part of making the jewelry. Hardening the wire can be accomplished by hammering, or by manipulating the wire in a process called work hardening.