Hi, when I used the inclusion pen on clear or coloured glass with mica powder uncapped fired at 700°C, it did not fuse to tack and rubbed off. I have also mixed mica powder with Glass line glue on clear glass and coloured glass, and it rubbed off when fired at 700°C uncapped. I am trialling mica powder with glass line glue capped with clear glass. When capped with clear glass what firing temperature would you suggest and what temperature can it go up to? What effect would this have when fired capped at 800°C?