CompuServe Messages

Al.. Tempering opal…I love it! Would that it were possible… As for tempering obsidian, sorry, I'm afraid I haven't a clue. I've done a small amount of glass blowing but never with a mind to learning about it's intricacies. As I recall from a roommate who worked in the plant manfacturing those 5 gallon Arrowhead water bottles, it took about 12 hours for the bottles to cool slowly. They were still hand-blown into the 1970's. I don't see any reason why you couldn't at least try tempering obsidian. Put on some safety glasses and see what happens. -Russ