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How Glass Products were Produced in 1950s


How crucibles were made

Today, combined glass raw materials are melt in platinum crucibles in electric furnace. In 1950s, when we started melting glass, we melt glass materials in unglazed crucibles made by clay in oil furnace. Clay crucibles were also manufactured in our company. They were manufactured mostly by hand, and it took about 6 months to make one clay crucibles.

This picture shows a red-hot crucible transferred to annealing furnace.


Melting in 1950s

This picture shows a crucible taken out from furnace

Glass temperature inside the crucible is more than 1200℃. It looks like a viscous and thick candy.
Glasses were melt for 1 to 2 tons, depending on specific gravity of the glass, at a time. Melting glass needed one whole day and night, and several workers had to work all night.
The crucibles were disposed after one glass metling.
One clay crucible which was left unused is placed as a big plant pot cover at our head-office entrance. If you have a chance to visit our head-office building, please have a look at it.


Inspection in 1950s

Internal inspection has been conducted by trained workers since then. This operation has not been replaced by inspection equipment.

All pictures were taken in 1950s.