Every time you work with precious metals, whether you're hammering, bending, drawing or rolling it, the metal becomes harder. Keep pushing it without softening it first, and eventually it can crack or even split. Annealing softens the silver or gold again, allowing you to continue shaping it without damaging it.
Annealing can also be important before soldering. When you've been bending or shaping your metal, there may still be some tension inside. As you heat the piece, that tension can cause your metal to move, spring open or change shape. Annealing first helps release those stresses, making the metal easier to work with.
Place your metal on a heatproof soldering surface and heat it evenly with your torch. Keep the flame moving across the entire piece rather than concentrating on one spot. The goal is to bring the metal up to its annealing temperature without overheating (and melting) it.
For regular sterling silver and many traditional gold alloys, a faint, dull red glow is a useful indication that you're approaching the right temperature. This is much easier to see in a dimly lit room. Turning down your lights can really help. In bright daylight, you might not see the color at all, even when the metal is already hot enough. I find it helpful to move the flame around my piece, this gives me a better view on the different colors.
The exact annealing temperature depends on the metal and its alloy. Sterling silver is commonly annealed at around 600–700°C, while gold alloys can require different temperatures depending on their composition. Some gold alloys need a different approach altogether, so always check the recommendations for the metal you're working with.
Thicker areas take longer to heat up, while thin sections can overheat much more quickly. Keep your torch moving and adjust where you apply the heat to bring the entire piece up to temperature as evenly as possible.
Once your metal has reached the correct temperature, avoid heating it any further than necessary. There's no need to make it glow bright red. Too much heat can cause damage and weaken your metal, and you don't want to accidentally melt your piece.
If you're working with sterling silver, you can quench it in water at this point. Unlike steel, quenching sterling silver doesn't make it hard again. The softening happens during the heating process.
With gold, the cooling method depends on the alloy. Some gold alloys can be quenched, while others need to cool more slowly to avoid unwanted changes in their properties. Always check the recommendations for the particular gold alloy you're using. Personally, I like to quench the gold I'm working with in methylated spirits. You can watch why and how I do this in my 'Q&A: Why I quench my gold in methylated spirits' video.
Once your metal has cooled properly, it's ready to be shaped again.
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Join me on PatreonSilver and gold are made up of tiny crystals, also called grains. You can't see them with the naked eye, but they're all packed together, each with its own arrangement of atoms. When you hammer, bend or roll your metal, you're not just changing its shape. You're also changing its internal structure. The crystals become distorted and tiny defects build up inside them. These make it increasingly difficult for the atoms to move past one another. That's why your metal becomes harder and less flexible the more you work it.
By heating up the metal to the right temperature, you're giving its atoms enough energy to rearrange themselves. Some of the internal stresses are relieved and new, relatively strain-free crystals begin to form, replacing the distorted ones. This process is called recrystallization. The result? Your metal becomes softer and easier to shape again.
So annealing isn't simply about heating up your metal. It's about changing what happens inside it. You're giving the metal a chance to recover from all the hammering, bending and rolling you've put it through. Pretty fascinating!
Take some scrap metal and heat it up until it melts. Try to figure out the color it had just before it melted. See how far you can take it without actually melting it. Give yourself some time to play around and to discover how the metals react.
These are general guidelines for traditional sterling silver and gold alloys. Special alloys, such as Argentium silver and certain white gold alloys, may require different annealing temperatures and cooling methods. And of course, never anneal jewellery containing gemstones without first checking whether the stones can safely withstand the heat.