Barium Sulphate is used instead of limestone in optical glasses.
The ready mixture of all raw materials necessary for the glass mass, as it comes for the melting into the pot or tank furnace.
A grinding method with a flat grinding wheel and with lined up grinding surfaces. With the bevelling glass is furnished with a geometrical surface grinding.
Mouth-blown glasses have a cap. The cap has to blast after the cooling process by concurrent heating. The incurred sharp edges are planished by regrinding again.
The most important tool for the production of mouth-blown glasses. It is a hollow iron pipe with a length of 100-150 cm. On one end extended the acceptance of the frit and on the other end is a mouthpiece for the glassblower. She was probably invented between 250 and 30 before Christ in Syria or Egypt.
This glass has a high resistance against chemical influences and differences in temperature. It is mainly used for cooking, roasting and baking crockery.
It is a rhombic grinding method, which is especially used for lead crystal glass (also called groundwood).
Bubbles are visible glass defects which is caused by insufficient refining during the melting process. They are also used as a refinement technique. However a "bubble" is called the blown up glass form at the pipe.
It is also called cellular glass. The frit is already interspersed with air bubbles during the melting process in the furnace and can finalise by mouth-blowing.