What is annealing?
Annealing is the process of heating a metal to a specific temperature before it’s worked on. Through this process of annealing, the precious meal is softened and made pliable. This will allow you to shape the metal into the jewellery piece you want. You might need to repeat the annealing process in case your metal work-hardens.
What is work hardening?
Work hardening occurs when the metal is repeatedly bent and shaped, putting stress on the metal and causing it to become less easy to work with. The repeated stress on the metal can cause it to snap because the molecules can no longer absorb that amount of pressure. The effects of work hardening can be reversed through the process of annealing. The annealing treatment will soften the metal, making it easy to work with once again.
What is the full annealing process?
When annealing metal, it will turn into an obviously darker colour followed by blackening. This is a chemical process known as oxidising. The annealing heat treatment process has to be continued throughout oxidisation until the metal reaches a red colour. This cherry red colour occurs when the metal has reached a critical temperature. Heat must be removed from the precious metal as soon as it reaches this point, otherwise you run the risk of melting the metal. It must then be placed in cold water. This is known as “quenching” the metal and the colour will last for a few moments until the metal relaxes. The annealing process can be repeated several times with one piece of metal – there is no limit. However, it is always best to anneal the metal as soon as you feel it start to harden and become difficult to work with. That way, you avoid causing irreparable damage to your piece.
It is not possible to predict the exact moment a metal needs annealing, and you will only learn the difference between a soft and hard state through practice. There are, however, a few basic tips that can help you.
Annealing sheet metal, wire & varying alloys
- Remove protective plastic before annealing. This can sometimes be kept when performing various piercing applications.
- Sheet: When buying sheet, always assume that it will need annealing.
- Wire: It will be easier to decide whether 1mm round wire is soft, however it’s less easy when working with a 5mm wire, therefore always anneal thicker wire.
- Pure 999.9 silver and 24-carat gold do not oxidise as they are intrinsically soft. They will only need annealing if extensive work has been performed.
- Perform your annealing with a soft flame by gently pushing it up the length of the metal rather than waving it from side to side.
- Ensure your metal is completely dry after quenching. This is essential as you do not want to rust the tools you work with. Check that your tools have no marks as they can be passed on to your metal.
How to anneal wire
Annealing thin wire: wrap it into a coil and tuck both ends back into the coil. This will prevent it from springing apart when heated. Place your coil on a soldering block and heat it wilth a soft flame. Keep moving the torch up the metal to avoid melting the wire. Turn the metal with a pair of insulated tweezers and anneal the coil on the other side.
Annealing thick wire: unlike thin wire, you will have to support your metal when heating it. Place the metal on the soldering block. Use a soft flame until it turns red then move along the wire to complete the process. Let the metal cool for a few seconds then quench in water. You can bend your wire to fit the pickle. Leave it until it has turned white. After removing it from the pickle, rinse and dry and you are ready to work!
Annealing silver sheet
- Cover your silver with a protective non-oxidizing powder. Keep the powder away from your soldered joints to avoid making the solder run.
- Remove the plastic coating from your silver wire and rub dry paper over both sides of your silver to remove the silver shine.
- In a saucer, form a thick paste by mixing powder and methylated spirit or water. Add a little more spirit or water to make it easy to paint over both sides of your metal.
- Place the silver sheet on a soldering block and heat it with a large soft flame. Like with wire, use the torch on your sheet until it has turned red and then move along the surface to complete.
- After cooling the metal, place it in warm pickle for 5-10 minutes. This will remove the protective powder.
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