Glasses & Materials

At Yankee Glassblower, Inc we utilize a variety of materials to meet the needs of our clients, this list may help you select the glass that is right for your needs:

Pyrex: a registered name of the name of the Corning Corporation, this refers to common Borosilicate Glass with an expansion of 32.5 x10-7 cm/cm/oC . It is readily available and can easily be heated and formed. Components are readily available such as ground joints valves and Laboratory glassware is “Pyrex” and has a maximum working temperature of 490 oC or 1500oF.

Fused Silica: commonly called Quartz, it has a rigid crystal structure therefore is not technically a glass. It is in essence a very pure sand that has been fused together. This creates a very high working temperature of 1200 oC and a very low expansion of 5.5×10-7cm/cm/ oC. Quartz is used when high temperature or concern from Sodium contamination is an issue. Softening temperature 1585 0C

Lime Glass: a soft glass with an expansion of 93.5×10-7 oC, it can be easily heated and formed and is often used in house hold windows. However, the high expansion rate increases the likelihood of thermal cracking.

Lead Glass: so named because of the 25% or more lead-oxide content in its chemical make-up, this high expansion glass (89.3×10-7 cm/cm/oC) can be sealed directly onto metals such as Platinum. It is commonly used in Neon signs and has been replaced commercially by Barium Strontium Glass for environmental reasons.

Corning 7052: this glass was specially designed by Corning corporation for creating a vacuum tight seal when joined to Kovar. It has an expansion of 47×10-7cm/cm/ oC and a maximum temperature of 420 oC

Aluminosilicate: a very dense glass, ideal for containing gases such as Helium and Hydrogen as well as alkali metals. This glass has a high expansion of 42×10-7cm/cm/ oC and a maximum temperature of 650 oC

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.  See Photo

Mullite: is a ceramic that can with stand temperatures above 1500C, it can be sealed to Pyrex if properly prepared. Mullite is susceptible to thermal shock.  See Photo