When brass is worked, through bending, hammering or shaping, it can start to harden and become increasingly difficult to work further. If your brass has gotten to this point but you still need to finishing shaping it, you will need to temper the metal in order to return it to its softer state. This process involves heating the brass to a point where the atoms are energized enough to rearrange themselves back into layers and then cooling it.
To temper brass, you will need to place the object in and oven or kiln and set the temperature to 565 degrees Celsius (so, you’re general home oven certainly won’t get hot enough). You will need to leave the object in the oven or kiln for at least 2 hours.
To remove the brass object from the oven or kiln, you will need to put on a pair of heat-resistant gloves (to prevent yourself from being burned) and use a set of long tongs. Place the brass object onto a firebrick or aluminium block and leave to cool slightly for around 3 minutes.
In the meantime, you will need to fill a large bucket or tub with water. Once the 3 minute cooling period is up, use the tongs to pick up the brass object again and quickly dip it into the water. Allow the object to sit for 8 to 10 seconds before removing it. The brass should now be tempered and cool to the touch.
When tempering brass, you should never remove your heat-resistant gloves, even during the cooling process, as the hot metal can quickly create boiling steam when it comes into contact with the water. It is also recommended that you wear safety glasses or goggles during the brass tempering process.