Stick with metal, which is closer compared to copper than glass.
Copper is a metal. I'd use glass if you could its cool cause its easier to clean and you can see the smoke pour through it.
Setzer12 Reviewed by Setzer12 on . Need some bong advice, SAFETY Is it safe to smoke out of a copper pipe, say for instance i have a nice bong but i have nothing for the bowl to connect to, , , srry my cams not working but ill try to draw it......> l l l l _ l l stem> \ l l <bong \/ \ (___) so im not sure if you understand my diagram, but that horizontal line above the peice labeled as a stem would be the Rating: 5