A is for Annealing – 2023 #AtoZChallenge

Welcome to my first 2023 A to Z challenge post on Tools of the Trade – Jewelry Fabrication.

As I was thinking about the challenge I realized writing about these topics in alphabetical order might be confusing, but I will do my best to clarify along the way.

Also, I use sterling silver in my work so my posts will most often be related to sterling silver as opposed to other metals. Sterling silver is 92.5% silver and 7.5% alloy. The alloy makes the silver stronger, but it is also why sterling silver tarnishes.

Note: Adequate ventilation and proper safety gear and safety procedures are critical when working in a jewelry studio. It is a good idea to maintain a notebook of the MSDS safety sheets for all materials used in your studio.

Annealing

Sterling silver is sold in different hardness and the one you choose is based on its intended use. For most applications that will involve soldering, dead soft is generally purchased. It is the most malleable.

As silver is hammered, or sawed, or run through a rolling mill, the silver gets harder – this is called work hardening. The molecules of the metal move around causing the metal to become difficult to move. It also becomes brittle. Continued attempts to move the metal at this stage can cause it to crack or break.

Annealing is the process of reheating the metal to relax the molecules (grain) allowing the metal to become malleable again.

Annealing temperature for sterling silver is approximately 1100°F but determining when the metal has reached that temperature is the trick.

• The metal is placed in a soldering pan, on a heat resistant surface such as a soldering block, charcoal, or fire brick.
• In a well-ventilated studio (with the lights dimmed) a torch (commonly an acetylene or an oxygen/acetylene torch) is continuously passed over the entire piece of metal until the color reaches a ‘dull cherry red’.
• Determining the color can be difficult in a brightly lit studio, so there are other methods that may be used to determine when the proper temperature has been met.
  • When the surface is coated with a paste flux (a flowing agent used in soldering), the flux will turn glassy clear when annealing temperature has been met.
  • When the flames bouncing back off the metal become orange in color.
  • When a line is placed on the metal using a permanent marker, the metal has reached annealing temperature when the marker line disappears.
• Once annealing temperature has been met, the metal must be quenched in water. If allowed to air cool, the internal structure of the metal will tighten again, reintroducing hardness.
• Caution: overheating silver will cause it to melt. It is always a good idea to practice on scrap metal if you are unfamiliar with the process.

Below is a short video from Halstead Jewelry Supplies that shows the heating of a piece of metal (copper in this example) heated to annealing temperature.