You can dip a (vase) form of clay on a stake into the molten glass, preen and solidify it and scratch off the clay again. Moulding, free blowing or blowing into a mould are possibilities.

Crown glass

A glass bulb was mounted on a metal rod and rotated. Thus a round glass disc was formed with a diameter of 80-90 cm. At the edge the glass became thinner.

Also cylinders were blown, cut open, reheated en flattened.

glashersmeltenLehr, cooling kiln or annealing furnace
To get the form tension out of processed glass and avoid rupture it is cooled slowly at 510 degrees in an oven at 24 hours.

Rhombus shaped panes
The crown glass disc is diamond cut, because this occers the least waste.
The center was cut out in a slightly larger pane. The two ends of which were still usable and formed a diamond. Also, at the outer edge triangles remain.
Because the rhombus panes were small, about 9 to 12 cm, they were processed as stained glass.