Yankee Glassblower, Inc. also combines glass with other high-quality materials for great results, including:
Fused Silica — commonly called quartz, it has a rigid crystal structure therefore is not technically a glass. It is, in essence, pure sand that has been fused together. This creates a very high working temperature of 1200°C and a very low expansion of 550x10-9 cm/cm/°C. Quartz is used when high temperature or concern from sodium contamination is an issue. Softening temperature: 1585°C
Kovar — is a nickel and cobalt alloy with a controlled expansion. It is ideal for any glass-to-metal seal when used with a compatible glass such as Corning 7052.
Mullite — is a ceramic that can with stand temperatures above 1500°C, it can be sealed to Pyrex if properly prepared. Mullite is susceptible to thermal shock.