I've been tumbling a sterling bracelet for over a day. Initially tried for a few hours, just not getting harder. I want it to harden so bracelet doesn't bend. Any suggestions? I use "mixed" jewelry shot, Dawn soap (just a drop or two) and enough water to just cover the jewelry. Hasn't done a thing after hours and hours of tumbling.
Tumbling only very slightly hardens the surface of the metal. You'll notice more of a "hardening" benefit when tumbling thin wire like you would use for creating ear-wires. For thicker gauges of wire, you've got to work-harden before tumbling or embellishing.
I harden core wires and the thinner flat/round wire used for bangles and cuffs. Before creating a wire bracelet, I harden the core wire by pounding with a hard plastic mallet or gently hitting with a ball pein hammer while the wire is on a steel bench block. Gently meaning that you hit the metal hard enough to work-harden, but not hard enough to flatten. This makes the wire much stiffer and better able to hold it's shape. In Sterling silver, the metal gets a wonderful springiness - perfect for keeping tension closures like a hook style clasp.
For bangles and cuffs, I harden the metal on a steel bracelet mandrel and also on a flat bench block. For final polishing og plain wire stock or sheet metal items, I use a buffing machine. "Wrapped" wire items go into the tumbler for a clean-up and polish.
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