Any wire going into another material needs a terminus to keep it from coming out.
I did christmas ornaments out of Sculpey and used a curved paper clip as my loop. Wedged into the center of the clay before baking, the U part made a perfect terminus.
You can do a loop, a T, an L, or even just a zig-zag before heating/ baking/ gluing your material(s). I'd adhere the wires inside the star first, and have each one about five times longer than you need before stringing all the beads on. Then you have plenty to work with to finish up the piece.
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