Glass Discussion & Research. NO IDENTIFICATION REQUESTS here please. > Far East (excluding China)
Research into Japanese pressed glass industry, c.1870-1900
David E:
--- Quote from: krsilber on December 15, 2008, 11:48:46 PM ---At any rate, perhaps the skills of the glassblowers were indeed a factor in the problems with making sheet glass? From what I've read, it seems like until about 1870 most blown articles were small, thin and fragile.
Just so I'm understanding things correctly, was the method of making sheet glass at the time that of blowing huge bubbles, slicing them open and laying them flat?
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The process of sheet glass manufacture involves blowing a large gob of glass into a sphere, then swinging the ponty rod to expand these into cylinders, cutting the ends off to create a tube, cutting down the inside centre of the tube, reheating the tube to a precise temperature (too much and it sags), opening and flattening the tube onto a table, then annealing. Assuming glass blowing is already a mastered skill, then the only part likely to have caused the men a problem is the swinging, but this is unlikely. Whether there was some other problem with the production process I cannot say.
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--- Quote ---BTW, the traditional cutting method was using iron bars and abrasives.
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Can you expand on this? I'm trying to picture how this worked. Were the bars and abrasives two separate methods, or used together? I saw a reference to early diamond point engraving, and wheel cutting was used by the late Edo period. Maybe bars and abrasives refers to diamond point (or "scratch," since diamonds weren't always used), and the abrasives were embedded in the bars.
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I have no idea, and was merely quoting Akiko's article. I imagine the bars were used along the length in a sawing fashion, with abrasives (as a paste?) to aid the cutting. Obviously a far longer and laborious method.
--- Quote ---I presume Akiko is aware of
Blair, Dorothy (1973), "History of Glass in Japan": 479 pages 240 b/w 37 colour.
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I would assume so - she is a lecturer at Tokai University so one would expect this to be available to her. But thanks, I will mention it.
David E:
I had an email from Akiko this morning:
--- Quote from: Akiko ---It was surprising for me that many people seems to be rather interested in sheet glass manufacturing in Japan than pressed plate!
When I have time I would like to join them, but I am too busy to answer many questions at the monent. I am sorry about that.
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I replied saying this was natural curiosity from researchers who take an interest in all manner of glass production. Hopefully she will have time to respond in the New Year.
krsilber:
--- Quote ---It was surprising for me that many people seems to be rather interested in sheet glass manufacturing in Japan than pressed plate!
--- End quote ---
Kind of surprises me, too! A couple weeks ago I wouldn't have dreamed I'd be interested in Japanese sheet glass.
I found a couple videos of cylinder sheet glass construction by Lambert's in Germany. The blowing part doesn't begin until about minute 7 in the first video, then continues in the second.
http://www.youtube.com/watch?v=gsOUyqGa9FM&NR=1
http://www.youtube.com/watch?v=u4gy7l6vp5I
...In case anyone is interested, I just found a whole chapter on the method. Oh! here's another good one..."conjuring the glaring globe (a gigantic dragon's eye) by artful whispers into a sheet of solid transparency." The chapter starts with an interesting description of pot making.
I also read somewhere about special annealing ovens (sorry, I don't know anymore which reference this came from; I've read several accounts and didn't keep track, but could find it again if anyone wants it). I still think making cylinder sheet glass would require a lot of new skill beyond that needed for blowing small glass vessels, but who knows if that was a factor in the struggle of Japanese factories to produce it - not I!
I don't know whether this holds any particular relevance here, but it's a timeline of a Japanese glass furnace maker, starting in 1892.
http://www.ihara-furnace.co.jp/english/en_corporate/cop_03.html Dead Link now here https://www.ihara-furnace.co.jp/english/en_corporate/cor-02_04.html
Frank:
When you study the earlier parts of glass history, you find most of the data is on window or bottle glass, vessels were not as widely used or made. There are distinct technology differences between those two branches and those differences defined how industries developed in any country - although politics also played a major role. Making glass vessels was often a secondary activity until later on and also demanded a different approach to produce a good quality product. The development of the technology for pressed glass was largely derived from the bottle industry but also took a separate path. It is interesting aside, that in glass art that the different threads of the technology have merged again.
krsilber:
I was using "vessel" in a generic sense, meaning something that holds something, and only for the purposes of comparing the difficulty of blowing table or decorative items vs. 4-7 ft (rough guess 1.15 -2 m) cylinders. As I understand it, the Japanese blown glass tradition had been small, thin wares.
What earlier parts of glass history are you talking about, and what do you mean by vessel? I would have thought there were always vessels made where glass was blown - that's not true? I don't understand.
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