Most things are safe. Unless you have some wierd idea and decide to use fiberglass. Even lead is safe as long as you don't drink the bong water LOL.
Coppper should be fine. It will corrode though, you may want to use brass instead.
Atomic Dragon Reviewed by Atomic Dragon on . Bongs: Glass vs. Acrylic, Safe/Unsafe Materials I'm looking into buying or building my own bong, or maybe both... 1.) What are the issues when it comes between Glass and Acrylic? 2.) When building your own, what are some common materials that're safe and unsafe to use? Where does Copper stand? THanks anyone who can help. Rating: 5