Topic: ID for heavy blue glass bowl

[Ekimp]

I must have too much time on my hands but was curious 
There’s another one here: https://www.ebay.com/itm/Large-Salad-Fruit-Punch-Bowl-Transparent-Blue-Glass-11-Diameter-3-1-2-High/372994484594?hash=item56d8342972:g:1rIAAOSwG21edA8S in America (searched blue fruit bowls). No help with maker I’m afraid but you can see the pattern is the same and the notches/fissures on the edge are in the same place. There maybe slight variation in the rims, but it’s hard to tell. You can probably judge better if you compare yours Roobarb, as your photos are a bit small and different angles etc.

Ps. Roobarb, please tell me you have a cat named custard   

[Roobarb]

Oh well spotted, thank you! Yes, that looks exactly the same - wiggles in the same place. This is the Blenko one which I thought it was similar to - but it's not quite the same https://www.ebay.co.uk/itm/Large-Vintage-BLENKO-Clear-Glass-Leaf-Bowl-12-5-Exc-Cond-Centerpiece-Handmade/222939566185?hash=item33e83bd069:g:iNUAAOSwHjta3N9Z

Haha, funnily enough Roobarb is my dog's nickname (real name Reuben) and I have joked before that I should call myself CustARd - this sounds very sad written down   

[Lustrousstone]

These are mass produced by machine. A simple two-part mould would be all that's required: a base plate and a plunger

[Ekimp]

I think it was probably made by centrifugal casting, rather than pressing. There is an interesting short video showing the process here: https://www.youtube.com/shorts/FexZcY8PUKw

[chopin-liszt]

There is mention of an air bubble, centrifugation would have eliminated that.
Centrifugation would be a very serious extra expense, I doubt it would be used in mass production.

[Ekimp]

I think centrifugal casting is/was used quite a lot, especially by the Scandinavians, thinking of ice glass candle holder type things.

Here is another short video and bit about the process from the Bergdala glastekniska museum: https://bergdala-glastekniska-museum.se/eng-html/eng-centrifugering.html

I doubt the glass would be liquid long enough to separate out bubbles, it looks to solidify quite quickly.

Surprised it gets through the h&s risk assessment

[Ekimp]

There is one on eBay said to be by Vaclav Zajic for Libochovice Sklo, designed in 1976. Pattern: 3559/140.

Searching online, that looks correct. There are plates and bowls, see link below. If you scroll down and click on the design, it shows more detail with references.

https://www.czechglassguide.cz/Zajic-Vaclav-c2_280_3.htm

[Ekimp]

See confirmation in the book Finding Balance, Design of Czechoslovak pressed glass 1948–1989.

Page 226 for photo and detail, says it’s made by “ring-less pressing”. Page 64 says ring-less pressing was introduced at Libochovice in 1971, incidentally, same page also says centrifugal casting introduced Libochovice 1976-1977.

https://www.msb-jablonec.cz/assets/virtualni_muzeum/knihy/hledani_rovnovahy_2021.pdf