Some Bullseye rods are graded as not suitable for fusing. I've found a neat list of these rods with an explanation that it doesn't affect lampworking and so forth... but no explanation to exactly why they aren't suitable for fusing. Is it a compatibility issue (and in that case, why would they be suitable for lampwork?) or do the colours die in the kiln or what?
I've just ordered a few rods of Bullseye, some of which are on the "not for fusing" list, and can try it out for myself once they arrive, but I'd just like to know if I they'll explode in the kiln and set the house on fire before I start experimenting ;D
There's some info here on the Bullseye site, don't know if that explains it
http://www.bullseyeglass.com/products/faq/#faq_043 (http://www.bullseyeglass.com/products/faq/#faq_043)
http://www.bullseyeglass.com/products/faq/#faq_045 (http://www.bullseyeglass.com/products/faq/#faq_045)
http://www.bullseyeglass.com/education/torchtips/ (http://www.bullseyeglass.com/education/torchtips/)
eta: I think it's more to do with the physical characteristics of the glass than anything?
It still isn't quite clear if it's just that the colours turn into muck, or if the glass itself can't handle it. I guess I'll simply have to try :)
You could try asking on the Bullseye forum - I know techie people from the factory are on hand to answer technical questions, as well as experienced makers
http://www.bullseyeglass.com/forum/ (http://www.bullseyeglass.com/forum/)
It's probably a colour thing - glass designed for lampworking often doesn't do what you'd expect in a full fuse. A good example is striking red - it tends to go opaque and get a gritty appearance - this is generally assumed to be a bad thing, although there's no reason why this couldn't be used as a feature...
Sean
I hadn't realised Bullseye have a forum :) I've posted the question there too now.
Bullseye's transparent pink striker sheet glass can turn an odd (and actually quite interesting) opaque bluish pink colour if you heat it too fast, but I've managed to get it to behave even in full fuse simply by heating it slower. Perhaps the "non-fusible" rods can be coerced in a similar way. I bought the rods for lampworking rather than fusing, but I think it's odd that they don't explain it further and that makes me curious :)