I recommend testing all the vitrigraph canes for your kiln formed pieces. Put very simply, the glass is taken to temperatures above what is recommended for compatibility. Even though this envelope is very often pushed, testing is still advisable.

In my experience, 'hot' colors have more of a tendancy to shift compatibility. This may be the experience of others as well, but nothing is out of the realm of possibility.

Having said that, and highly recommending testing for fusing, the glass used is sheet glass and taken to 1700 degrees very briefly. I have used the vitrigraph canes very successfully in kiln formed pieces, but my results may not correspond with yours. I have not, at this point in time, had compatibility problems with these used in flame worked beads. I wouldn't sell them if I did.

To better understand this, and put much, much better than I, Page 6 of the Bullseye #4 catalog and TechNotes 3 & 4 (both found on the Bullseye website) are definitely worth the time to read for a general understanding of this. (I in no way imply that Bullseye is in any way responsible for anything written on this website, or any glass there-in. I only refer to thier research as the highest industry standard in education in the glass arts. In my opinion of course.)