is part three of a multi-part series on devitrification. Click
here to go to part one.
5. Although a borax solution or a
commercial product such as "Spray A"or "Superspray" can help prevent
devitrification from forming, these sprays should be used sparingly.
While the thin layer of flux they leave on top of the glass helps
protect the glass from devitrification, it's not necessarily
permanent and may sometimes deteriorate over time.
6. Areas of devitrification will tend
to have a different COE than areas that have not devitrified.
If reheated, they will also tend not to melt as readily as "normal"
7. It's a good idea to avoid re-fusing
or re-melting glass that has devitrified and combining it with
clear, non-devitrified glass. The resulting mixed glass will
tend to be unstable and may crack or fall apart when cooled.
8. Devitrification should not be
confused with tin bloom (a similar imperfection which appears on the
tin side of float glass), with mold marks or stretched glass from
slumping procedures, or deposits on the glass from other substances,
such as glue, binder, or wax residues.
here for more on the causes of devitrification.
Copyright 2005 Brad Walker.
All rights reserved.