What is Work Hardening?
Work hardening is a term that refers to certain metals’ tendency to stiffen up as they are manipulated. Very often, we use work hardening intentionally to give strength to soft metal to help it hold its shape. We can also use it to add springiness, as is helpful in a latched hoop earring or clasp.
Work hardening techniques allow us to deliberately change the temper of the wire that we want to work with and force it into a stronger state. But keep in mind that work hardening will also occur simply through the process of working with your metal, whether it is your intention or not.
Basically, jewelry wire can be purchased in three different levels of hardness, or ‘temper’: dead soft, half hard, and hard. Dead soft wire is very easy to manipulate, but it is too soft to hold its shape after you form it, which would be a problem in some cases. For example, if you want to make a pair of ear wires with dead soft wire, you will need to harden up the wire either before or after you make the ear wires so they don’t stretch or bend out of shape.
Sometimes half hard wire might need a bit of work hardening as well, depending on the gauge (thickness) of the wire. Hard wire would usually not need to be work hardened at all, as it is already in the strongest form of the metal and holds its shape very well once formed.
How Does Work Hardening Work?
Without getting overly scientific, just consider that any time we are working with wire and moving it – whether through bending, twisting, pulling, coiling, hammering, etc. – we are moving the metal’s molecules and squishing them closer and closer together. The closer the molecules are, the harder the wire is to bend.
Soft metal basically has a very loose molecular structure. I like to think of it as nice and relaxed. It is very pliable and forgiving in this state. If you bend it in the wrong place, it’s very easy to just bend it back and start again. But remember – the act of bending the metal and bending it back again is compressing those molecules and hardening up the metal at that point. If you continue to bend and unbend the metal in the same spot over and over again, you will notice it getting stiffer and stiffer and it will eventually just break!
That’s because as metal gets harder, it becomes more brittle – the more you push it, the closer it gets to a breaking point and will just snap when it’s had enough! (Like me, when I’m tense and uptight :)
With that in mind, it’s important to work harden the wire just enough for the design’s requirements. If you go overboard, you risk weakening the design by making it too brittle, which completely defeats the purpose of work hardening!
Work Hardening Different Wire Materials
The metal properties described above apply to non-ferrous metals like silver, gold, brass, and copper. And although they are similar, they still each have their own characteristics that are worth becoming familiar with.
Of course there is also a variety of other jewelry metals out there that may behave entirely differently, so you will want to do research on the properties of your particular material before working with it. My experience with aluminum wire, for example, is that it becomes brittle and will break more quickly instead of hardening up and becoming stronger like the other metals I just mentioned. Instead of trying to work harden aluminum wire, it is probably better to just start with a thicker gauge for the strength you need.
My suggestion is to practice with a few scraps of the materials you want to work with – and be sure to do this for each new metal you try – so that you can see and feel how easily the metal responds to the work hardening method you plan to use, or even just how it responds to being worked with your hands and your tools. The best way to familiarize yourself with a new material is to get it in your hands and work with it!
Read all about Jewelry Wire Materials for more information.
Can You Undo Work Hardening?
While you can harden soft metal, you can also reverse the process by heating the metal to a specific temperature (usually with a flame torch) to rearrange the molecules back to their relaxed softened state. This process is called ‘annealing’ and is generally not needed in basic wire working, so we will save annealing for another lesson!
After all this talk about when and why to work harden your metal, you are probably wondering how exactly to go about doing it.
There are several methods for work hardening metal, including pulling, hammering, twisting, and tumbling. I have detailed all these methods in a separate article in the interest of not having the longest blog post in the history of the internet ;)
Read How to Work Harden Jewelry Wire to see how to use these techniques!
If you’re new to making wire jewelry, you will find the rest of this series All About Jewelry Wire very useful!
Part 1: Wire Gauge Sizes
Part 2: Wire Hardness
Part 3: Jewelry Wire Shapes
Part 4: Jewelry Wire Materials
Part 5: Which Gauge Wire for What?
Part 6: (you are here)
Part 7: How to Work Harden Jewelry Wire