I like to make my own earwires and findings from sterling wire. I've heard of tumbling them to harden them, but is this necessary? If so, how do I go about doing that? What equipment do I need to strengthen sterling findings (without changing their texture)? Thank you!
When you need to work harden the entire length of wire or finished design, tumbling in steel shot is a great option. It will work harden sterling silver without marring or leaving a texture on the metal. Another great thing about tumbling your metal is that it cleans and polishes at the same time. For instructions on how to tumble with steel shot, review the how-to video on tumbling and polishing listed in the resources below.
If you have a finished piece like a necklace and only want to work harden certain parts, or it is too large to fit in the tumbler, then hammering with a rawhide or nylon mallet will be the better option; each of these will harden the metal yet not mark it. Using a mandrel to maintain the shape of the piece while hammering is also recommended. After hammering, you can work the wire with a burnisher to harden even further with the extra advantage of shining the silver.
Tip: Starting your design with half-hard wire can reduce the need to further harden your sterling silver.