This website is bilingual, written both in Swedish and English. For those of you preferring another language, we provide "google translate". Be aware that automatic translation sometimes gives very odd results...

Denna webplats är tvåspråkig, finns på både svenska och englska. För er som föredrar andra språk, har vi lagt till "google translate". Kom ihåg att automatiska översättningar ibland ger konstiga resultat...

- Glass melting furnaces
- Glass pots
- Pressing, a general descripion
- Pressed glass, some examples
- Centrifuging
- Vacuum flasks




Centrifuging glass

In the 1940ies some people started to experiment with the centrifuging of glass, as a technique to manufacture thicker bowls. One of the anecdotes often told is that NN saw someone using a butter churn and started to think.
A more plausible story is that NN saw a milk separator...

So, who was NN, who was the first?

A common opinion says it was Sven Palmqvist at Orrefors, another says it was Magni Magnusson at Skruf. The idea might have been "in the air", but fact is that Palmqvist was given both a Swedish and an American patent.

According to the book Sven Palmqvist - glaskonstnär (ISBN 9188 712 86 9) the first patent application was filed in 1943, for a "device to manufacture glass objects".
This device was rather primitive: hand operated, with a removable mould which had to be detached to tip out the centrifuged object.
One problem with the first centrifuge was that it did not have a stop collar at the top - the book mentions (my translation): "The molten glass could, at high speed, escape over the top of the mould, thus burning the pants of the operator".
Another patent application was filed in 1946, now for a bettered device: it now had a collar, and was also powered with an electric motor.
At this point Magni Magnusson intervened: he had filed an application in 1941 for something similar. In 1951, the case was resolved, and the Swedish patent no 133629 was awarded to Palmqvist (see link above).

The centrifuge was further developed - first the material of the moulds (to reduce the need of further processing), later the moulds got an ejector at the bottom to facilitate removal of the objects.

The technique was not loved, to begin with. It did not take off until the manager at NK declared they wanted the centrifuged bowls as part of their "Swedish grace" goods - in 1954 Orrefors started manufacturing the series "Fuga", and it was an immediate success.


Later, the technique was adopted by several glassworks, but it can be said that Orrefors was the leading company.

We show several examples of the technique - some Fuga bowls, but also a couple of more "advanced" objects. Lars Hellsten is one of the designers who has worked extensively with the technique.

Fuga in two sizes
centrifugated bowl
Corona

Below a short video showing centrifuging at Bergdala in the spring of 2017.

Many people do not think it "good English" to use centrifuge as a verb. However, professor Keith Cummings uses it as such, in the book A history of glassforming, ISBN 0-7136-5274-8, from 2002 - so I consider myself being in good company.