How I pressed the copper wire into the glass:

I put the copper where I wanted it and then put textured clay plates on either side of each glass ring to give the smooth blue part of the glass some texture to go with the sand on the other side and then a heavy brick on top and slumped the glass again until I was pleased with how far the copper wire had gone into the glass.

I also ground away some of the sand on the ends so the blue light could be seen from the side and not just from the back.