Borax is a glass making flux used to reduce the melting temperature of glass.
It is almost colourless - grey, white, or yellowish; seldom bluish or
greenish; and colourless in transmitted light.
The chemical composition of
Borax is: Na2(B4O5)(OH)4 · 8H2O
It has a hardness rating of
2 – 2.5, about half that of glass at approximately 5.5.
The
melting point is 878°C. At this
temperature borax dissolves numerous metal oxides. In spite of this high
melting temperature, it acts as a flux reducing the softening point at
the surface of the glass at kiln forming temperatures.
The specific
gravity of borax is approximately 1.7, considerably ligther than glass at ca.2.5.
Borax is sparingly soluble in cold water, although readily soluble in
boiling water. It is insoluble in ethanol.
No comments:
Post a Comment