CompuServe Messages

>> tempering Sorry if I confused everybody – I meant annealing, of course. >> 5 gallon Arrowhead water bottles, it took about 12 hours I can understand that – they contain a lot of glass, and carry a lot of weight. You don't want any stresses. For ordinary laboratory projects you learn what rate and how long to wave it thru the flame. Well-equipped labs sometimes have an annealing oven. Quartz is easy – it doesn't usually require it. OTOH, you have to work it at white heat wearing welding glasses, which is a pain. I think I will try some obsidian. It won't be a very precise experiment, since I don't know how to measure stress before cutting, but if I get 3 or 4 in a row which don't explode, I'll consider it a success. Al