Refined and cleaned? Glass fining
In everyday life, something is refined when it is free from imperfections or defects. We also speak of refined people, who are elegant, polished and cultured.
With regard to removing imperfections, the term is also used in glass production. The process is referred to as glass refining or fining. It simply describes the removal of bubbles from the molten glass,
as of course bubbles in the finished glass would constitute a defect. Basically, small bubbles are swept along by larger bubbles as these rise to the surface more quickly. A fining agent is added to the batch to make this work.
Experts differentiate between two basic methods: chemical fining and blow fining. The latter involves a gas being blown into the glass to reduce the number of bubbles in the glass. The chemical fining process is the one described above. Glass fining is also said to be possible with ultrasound.