Complex sentence: The ideal wire will be easy to bend until in its final shape but then very stiff, but since this wire does not yet exist, when making wire wrapped jewelry, the artist or crafts person may harden the wire as one step in making the jewelry.
Split into simpler sentences: The ideal wire will be easy to bend until in its final shape but then very stiff. Obviously, this ideal wire does not yet exist, so, when making wire wrapped jewelry, the artist or crafts person may harden the wire as a step in making the jewelry.