WarmGlass.com

I've been making drop ring bowls. Usually I cut the rim off the top, and for every two drops
I can add some clear and recycle those rims into a new bowl. My question is whether there is
a limit to how often I can do that. Some of the glass in each rim is likely to be "new" glass and
much of it will be "old" glass, fused possibly several times. Am I likely to get into trouble if I
just keep doing this time after time?

Thanks,
Emily

Emily Will
Fused Glass Artist
http://IntenseGlass.com
919-556-7414

Bullseye's testing goes as far as 3 firings (to 1500?) and after that you're on your own. I've found incompatibility shifts in the yellows mostly, the rest of the colors don't seem to care how many times they're fired.
I have no idea how Spectrum tests their stuff.
You could do your own tests...

Marty wrote: I've found incompatibility shifts in the yellows mostly, the rest of the colors don't seem to care how many times they're fired.

I've also seen shifts in whites (especially the opaque) and in aventurine green.

As for System 96 glass, yellow and white have also been troublesome.

If the reds are on the orange-ish side, especially the transparents, they'll first opaque up, and can also shift with repeated firings. The blue-reds don't seem to have that problem.

I suspect it's not the number of firings but the total amount of heat the glass has been subjected to that really counts. I can get away with lots of low-heat, tack-fuse firings when I'm building up layers for depth, but maybe only one or two high-temp firings hit the limit.