Many furnace builders came from Bohemia. I knew everyone. The Passauer furnace builder had his business in Bohemia. They have gone abroad, everywhere they were known. But by the end of the war all went.
The whole furnace construction in Theresienthal was done through the Bohemian furnace construction company Passauer. After the war, it has taken to Wagenbauer in Zwiesel.
Glass furnace builder, born 1930
Long time ago it was fired with wood, there in the Kieshütte, there was a large circular saw standing. There they cut the wood, and the wood was driven over with the trolley and thrown over into the generator to make the gas. Down there was the fire, from there, the gas was introduced into the furnace.
And then later we've fired with coals. Coal gas has been made since. That was a big change. The screech, because you have to have used hearing protection.
Then we have for a while fired with oil, until it has been converted to LPG, and then natural gas came, that’s how it all was.
Section head, born 1931
Each little factory has a different glass composition. The quartz sand is the main material.
So, the silica sand, soda, lime, potash, borax, nitric oxide, lead oxide, and then other oxides when a coloured glass is made. The potash is the most expensive material, and that brings the glass to shine.
Glass smelter, born 1910
The melt takes ten hours, to nearly 1500°. When the glass is ready, then it is being brought to a lower temperature. That's going to take another two hours.
And then the smelter has to monitor the furnace again.
When the glass blowers come, the furnace must have the right working temperature.
Glass melter, born 1910
The pots last differing times, it comes down to what you melt. When lead is melted, the pots last 16 to 18 weeks. We then certainly have to change them because they risk breaking when they are filled them with cullet. With crystal we can have the pots 25 to 30 weeks perhaps.
Manager, born 1946
We have got paper cuts that were as big as the glass has to be. After this cut, I turned out the shape. If you have pushed the paper cut into it, and it's been perfectly horizontal in it, it fits the bill perfectly. This has to be exactly right.
And then you have knocked the form off the lathe, split it apart in the middle and fixed it together with clamps. Then the mold can go into the works.
Wooden mold maker, born 1928
