crown glass
This method for the manufacture of flat glass had been invented
in Germany in the fourth century A.D.
The method is as follows (see image):
1. A blob of molten glass is taken from the furnace with a blowpipe.
2. The blob is inflated.
3.
The resulting balloon is flattened by pressing it against a flat surface.
4. On the other side of the balloon, a solid iron bar, the "punty" rod, is attached, and the blowpipe removed.
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5.
The opening is stretched as far as it will go, resulting in some
sort of wide bowl.
6.
This bowl is swung around rapidly so that it turns into a round,
flat disc.
7.
The central knob, where the “punty” rod was attached, is cut out, and the remaining flat segments are then cut into lozenges. |
