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1. Glass Production
Technics
Presented by Zain Ansari (F16MT27)

2. Glass
Production
Techniques
An amorphous, inorganic substance made by
fusing silica (silicon dioxide) with a basic oxide;
generally transparent but often translucent or
opaque. Its characteristic properties are its
hardness and rigidity at ordinary temperatures,
its capacity for plastic working at elevated
temperatures, and its resistance to weathering
and to most chemicals except hydrofluoric
acid. Used for both utilitarian and decorative
purposes, it can be formed into various shapes,
colored or decorated. Glass originated as a
glaze in Mesopotamia in about 3500 BCE and
the first objects made wholly of glass date to
about 2500 BC.

3. Glass-making Techniques and Other Glass Terms
Virtually all the techniques of glass-making in use today were
known in antiquity. The tools have not changed essentially since
the discovery of glass-blowing, although on technical level
furnaces, chemistry and mass-production methods have been
improved. Most of the advances in glass manufacture are the
result of the industrial revolution; mechanical pressing, acid-
etching and sand-blasting are techniques that have evolved only in
the last two hundred years.

4. Core-Forming
• the earliest method of making glass
vessels is known as core-forming. Small
containers were produced by trailing
molten glass over a shaped, clay core
fashioned on the end of a metal rod.
Upon completion, the rod was removed,
the vessel annealed (gradually cooled),
and the clay core scraped out. The
Erimtan Collection contains only one
example of a core-formed vessel. It
represents one of the last types made by
using the technique.

5. casting
This process involved the shaping of molten
glass in a closed mould or over an open former.
The earliest use of casting is found in the
production of mosaic glass vessels during the
Late Bronze Age. They were made by fusing
together thin slices of coloured glass made
from canes.
After casting, the vessels were allowed to cool,
and then they were usually cut and ground into
their final form.

6. Blowing
The combination of the blow-pipe and the
knowledge of inflation revolutionized the
glass industry, enabling craftsmen to make
vessels more quickly, at less expense and in a
greater variety of shapes.

7. Mould-blowing
• This technique developed from the
invention of glass-blowing, probably in the
first quarter of the first century AD. It
allowed the glass-maker to replicate designs
and shapes at will, using a pre-made clay,
metal or wooden mould.

8. Pattern-moulding
This was a method in which a gather of glass was partially formed in a mould. The pattern
thus created was then expanded and usually spiral-twisted during the re-inflation of the
vessel.

9. • Tralling
The application of glass threads, often in a
contrasting colour, gave added interest to free-blown
glass vessels
• Cutting
Cutting as a type of decoration was a separate
operation carried out when the vessel was cold. The
Romans distinguished clearly between the glass-
maker and the glass-cutter, the former being called a
vitrearius and the latter a diatretarius. While the
glass-blower was principally involved in the
manipulation of hot glass, the glass-cutter employed
skills that were more closely related to those of the
gem-cutter.

10. Fire-polishing
The re-introduction of a vessel into the
furnace in order to soften and thus smooth
out any irregularities on the surface of the
glass.
Marvering
Rolling softened glass over a flat surface,
usually in order to smooth an added trail
decoration into the side of the vesse

11. • Pontil
A metal rod that enabled the glass-maker to hold and manipulate an object while
working on it. After blowing, the pontil was attached to the bottom of a vessel
while the rim, handle(s) and other decorative elements were added.
• Kick
A depression in the bottom of a vessel, usually caused by pressure exerted in the
application of the pontil.

12. • Weathering:- Over time the composition of glass can deteriorate, creating a chemical
deposit that often flakes off to leave a pitted and iridescent surface. This not only
obscures the original colour and transparency of the glass but can also destroy the
decorative details and, in extreme cases, the vessel itself.

13. Thank You
See you next time