I am looking for a way to harden copper outside of work hardening.  I have made an omega out of copper wire and I don't want to hammer it.  I have tried tumble polishing it but it is still very soft.  Is there a way to flame harden copper or bake it like Argentium?

 Pure copper can be hardened only by cold working. Flame hardening is not possible.
However, there are hardenable copper alloys. Search in the Internet for a  suitable alloy .

You can also the following do. Clamp one end of the wire in a vice. Take the other end in a pliers.  Straighten the wire as much as possible. By that the wire get harder. Bending  the Omega after that
Edmund

www.emailkunst.de

 But that is not a copper alloy but a 750 gold alloy.  And the price is many, many times higher.