Eye protection is important when melting glass in a flame for several reasons.
- Protection against glass fragments. Glass, especially soft glass, can sometimes shatter if placed directly in the flame. Safety glasses protect your eyes from flying shards of glass.
- Work more efficiently. Melting hot glass in open flame produces a yellow or orange glow called sodium flame. This sodium flame can be intense and obscure the true colors of the glass, making it difficult to see the workpiece accurately. Didymium goggles are equipped with lenses that filter out the sodium flame so you can see into the flame.
- Protection against UV and IR radiation in hard glass processing. The need for protection against UV and IR radiation becomes even more important when working with hard glass such as borosilicate or quartz. These glass compositions require higher temperatures during the lamping process, which results in more intense UV and IR radiation from the flame.
Which glasses?
When working with soft glass, didymium or Philips202 will suffice. If you work (often) with borosilicate glass, it is recommended that you wear glasses that provide higher protection against UV and infrared radiation while still filtering out sodium glow.
Welding goggles are not such a good idea because although they protect against the very intense UV and infrared radiation released during welding processes, they are often very dark tinted and do not filter the sodium glow.
