Glass Blowing for Vacuum Devices

Didymium Glasses

When the torch flame reacts with glass containing sodium, a bright orange flare occurs. This often obscures the work and can make operations more difficult as a result. Fortunately, sodium emits almost all light at only two wavelengths that are very close together at 590nm. This makes it possible to almost completely filter out only the orange flare.

Didymium glasses are almost opaque at 590nm. Wearing them can make a real difference to the standard of work achieved. The work is much easier to see when in the flame. It becomes much easier to see when the glass is at the correct temperature as the red glow can be seen even with the glass in the flame.

The short movie below shows what a difference didymium glasses make. When progressing beyond the early practice stages of glass work, it is well worth buying a pair of didymium glasses. If working with hard glass that requires high working temperatures, an additional UV and IR filter for protection is probably also a good idea. For soft glass this is not really necessary.