Yo why would you tell him anything is safe, You are either mean or you jsut dont know. Stanless steal and brass are the only metals you should be using. Other metals wont kill you but that doesnt mean they are safe to smoke out of, the have fumes that are really bad for you. as for the chamber part, it doesnt really matter between glass and Acrylic. but you wouldnt likely use a metal bowl for a glass bong anyways. Glass bongs do taste a hell of alot better though.