Actually the Delphi catalog, page 141, says it's zinc rebar. I got it confused with the Strongline Flex. Steel reinforcement, page 130. That's copper coated steel. We started using the Strongline but decided it wouldn't be enough support. Thanks for the interest. We enjoyed the project a lot but glad it's done & installed!

 I looked at the colored picture in the book and picked out similar glass I had in my scraps. I used clear English Muffle for the background. Glad you like it; had fun doing this project. I was glad when done after 160 (some very tiny) pieces!