Author Topic: Opalescent Art Glass Basket  (Read 3545 times)

0 Members and 1 Guest are viewing this topic.

Offline Adam

  • Glass Professional
  • Members
  • ***
  • Posts: 355
  • Sowerby 1949-56, Davidson 1956-61, Jobling 1961-72
Re: Opalescent Art Glass Basket
« Reply #20 on: March 05, 2008, 07:25:19 PM »
Ignoring the thing stuck on the side later, I am confident that Christine is correct in her opinion that this was pressed in one piece.  The mould was oval and the handles, at the time of pressing, would lie horizontally outwards, level with the top rim.  The bottom half (as pressed) of the handle would be formed in the mould body, while the top half would be formed in the top ring.  Hence the mould mark on the handle.

After reheating, all the reshaping would not be difficult.  The article, as suggested, could have been held in a snap, aka spring punty.  The mould maker has clearly made the handle to look applied and hence to look more up-market.

Adam D.


Offline Sid

  • Members
  • **
  • Posts: 393
    • Canada
    • Glasfax
Re: Opalescent Art Glass Basket
« Reply #21 on: March 05, 2008, 11:27:23 PM »
Adam:

I was hoping that you would see this discussion and comment.  The postings you did a few years ago on moulds was excellent in explaining the technical side of these things.

Thank you



Offline jsmeasell

  • Author
  • Members
  • ***
  • Posts: 226
Re: Opalescent Art Glass Basket
« Reply #22 on: March 06, 2008, 02:46:12 AM »
The key to understanding these pressed handles (and the decorative top edge of the piece) is the relationship of the ring to the mould. Quite a few Sowerby pieces have handles made in similar fashion.

At Fenton Art Glass, we frequently press items and then change the shape dramatically by warming in and finishing.
James Measell, Historian
Fenton Art Glass Co.


Offline Bernard C

  • Committee
  • Members
  • *
  • Posts: 3165
  • Milton Keynes based British glass dealer
Re: Opalescent Art Glass Basket
« Reply #23 on: March 06, 2008, 08:14:22 AM »
Adam — Grateful thanks for your authoritative explanation.

Adam & James — I have to admit, much to my shame, that my knowledge in this area is woefully inadequate, particularly for one who attempts to explain to others how glass was made.   Perhaps my enthusiasm masks my lack of knowledge.   In particular I really don't understand the ring element of a mould, how it works, and what its purpose is.

Would you be so kind as to recommend some basic reading?   No concerns about out-of-print publications, British or American, as our inter-library loan service here in the UK functions efficiently.

... I don't understand "sprung punty" either — but that's a different subject ...

Back to this lovely basket — when I first saw the photographs Sowerby sprang to mind.   The colour, shape, and fineness of detail are all right for Sowerby.   I haven't yet acquired Glen's material on CD (there always seems to be another publication that's more important), so I am missing pattern book XI which should be checked for this basket.   I was interested to see that you, James, had similar thoughts about the possible Sowerby origin.

... and finally, could the acanthus leaf decoration have been applied by a different glass house?

Bernard C.  8)
Text and Images Copyright 200414 Bernard Cavalot


Offline krsilber

  • Members
  • **
  • Posts: 1015
  • Gender: Female
Re: Opalescent Art Glass Basket
« Reply #24 on: March 07, 2008, 08:52:03 AM »
What a pleasure to discuss glass with such a learned group!

"I have to admit, much to my shame, that my knowledge in this area is woefully inadequate, particularly for one who attempts to explain to others how glass was made.   Perhaps my enthusiasm masks my lack of knowledge. "

I hope that's no reason to be ashamed - sounds like me!

I'm not very knowledgeable about molds, for I'll take a stab at the mold ring question - pure conjecture, understand, but I like that kind of thing sometimes, even when my hypotheses are wrong.  I'd guess it's a part of a mold that fits on top of two or more other parts that form the sides of the mold.  It would be donut-shaped, and the plunger would come down through the middle.  In this case it would bear the negative of the inner half of the handles.  This would address my earlier uneasiness about the idea of having a patterned plunger.  ...Now to wait and see where I'm wrong!

I'd never heard of a spring punty, but snaps or snap cases are sort of like tongs, with curved ends designed to hold a piece of glass. 

Unless the leaf is glued on (highly unlikely), it couldn't have been applied by another maker.  Well, it may not be physically impossible, but it would involve very slow reheating to a temperature at which it was hot enough to fuse with the leaf, and the two formulas would have to have compatible coefficients of expansion.

Having said that, I'm hoping I'm wrong.  I used to have a flower frog that I strongly believed was made of a piece of glass that had glass ropes added to it at a later date.

"The pinkish colour is merely the reflected 'visible' radiation from the UV source. With a fine spectrum UV source (with no visible light) only fluorescence would be seen - the rest would be black. Lamps are available in the reprographics world but are lethal to the eyes."

This may be the case with this basket, or opalescent glass in general, but it is not always so.  I've seen modern colorless glass fluoresce a pinkish color of a different hue from the UV lamp I was using, and have enough experience with using the lamp to usually know when something is fluorescing or reflecting.  Mr. Vaselineglass's spectroscopic examples were all uranium-doped, but there are other minerals used in glassmaking that fluoresce or enable fluorescence in longwave UV light (manganese, for instance).  Martin's very interesting comments about neodymium absorption spectra in different lights are about a different phenomenon.  Fluorescence is when light (or chemical) energy results in the excitation of molecules, which then give off light of a longer wavelength.

Phew, sorry about the long post!  I love these subjects.

Oh, forgot to answer this:  "BTW — Apologies, I had to ask — Are you a descendant of the Silber of Silber & Fleming, whose c.1890 mail order glass and china catalogue is so useful to us today?"

No, sorry, never heard of 'em!  Is this a common reference on your side of the pond?
Kristi


"The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science."

- Albert Einstein


Offline Frank

  • Author
  • Members
  • ***
  • Posts: 9379
  • Gender: Male
    • Glass history
    • Gateway
Re: Opalescent Art Glass Basket
« Reply #25 on: March 07, 2008, 09:18:29 AM »
Sprung punty a.k.a. Gadget and other names. I'll start a new topic.
Frank A.
Please help preserve glass web-sites for posterity by donating to The Glass Study Association a non-profit organisation.
Scotland's Glass - Ysart Glass
Glass Zoo - Glass Study.COM
Commercial Czech


Offline mrvaselineglass

  • Author
  • Members
  • ***
  • Posts: 514
    • http://www.vaselineglass.org
Re: Opalescent Art Glass Basket
« Reply #26 on: March 07, 2008, 01:50:46 PM »

Patents are another path to some data, see US 1629248 May 1927 Uranium red glass.


Frank:  I looked for this and just could not find it.  I did a search of that number and came up with a machine of some sort.  I then did a search of "red AND uranium AND glass" and found nothing that old.  I was looking in the patent section, as that is what you mentioned.

Dave


Offline Frank

  • Author
  • Members
  • ***
  • Posts: 9379
  • Gender: Male
    • Glass history
    • Gateway
Re: Opalescent Art Glass Basket
« Reply #27 on: March 07, 2008, 03:05:39 PM »
Ooops! It is those dyslexic fingers got the number wrong

Patent number: 1629648
Filing date: Jul 22, 1922
Issue date: May 24, 1927
Inventor: WARREN F. BLEECKER

http://www.google.com/patents?id=jpNpAAAAEBAJ&printsec=abstract&zoom=4&dq=1629648
Frank A.
Please help preserve glass web-sites for posterity by donating to The Glass Study Association a non-profit organisation.
Scotland's Glass - Ysart Glass
Glass Zoo - Glass Study.COM
Commercial Czech


Offline Adam

  • Glass Professional
  • Members
  • ***
  • Posts: 355
  • Sowerby 1949-56, Davidson 1956-61, Jobling 1961-72
Re: Opalescent Art Glass Basket
« Reply #28 on: March 07, 2008, 10:11:05 PM »
Kristi - Yes!!  Your understanding of the ring is spot on.  I would only add, to try to help Bernard et al, that it is worth thinking what would happen if there were no ring.  The plunger would come down into the mould, the glass would rise up between the two and only stop, quite unevenly, when either the pressure was taken off or the glass set.  When the plunger was withdrawn it would be a gamble whether the messy-looking article remained in the mould or went up with the plunger.  The ring, therefore, serves two purposes.  One, it forms the upper edge of the article and two, it holds the article down while the plunger is withdrawn.

Re the attached bit on the outside of the basket, I don't see why, if it were formed in some way and kept hot it could not be attached to the article while the latter was being re-shaped.  Possibly a quick re-heat if necessary.  As someone mentioned, the two glasses would have to be roughly similar, expansion-wise, or something would go off pop at some stage.

Adam D.


Offline krsilber

  • Members
  • **
  • Posts: 1015
  • Gender: Female
Re: Opalescent Art Glass Basket
« Reply #29 on: March 08, 2008, 12:45:43 AM »
Oh, good!  It's gratifying to know my understanding of these things is growing.

Adam, you have some dates and glassmakers under your location - are these companies you worked for?

This doesn't relate to Ken's basket, but as long as we're talking about molds, I have another question, this one about "skeleton molds."  A few weeks ago someone posted a vase on the ebay Porcelain, Glass and Pottery board, and included a photo from a book that showed a similar pitcher and part of an explanation about these molds (see thread http://forums.ebay.com/db2/thread.jspa?threadID=2000493395&start=40).  Frustratingly, some of the text was excluded, and I've been curious about them and how they are constructed ever since.  I picture a type of blow mold with multiple panels held together by rings, and holes where the glass was allowed to protrude. Here's a sketchy drawing of what I envision.  Is this near accurate?
(http://i99.photobucket.com/albums/l288/krsilber/skeletonmoldmaybe.jpg) 

(Has anyone seen any pieces by Stevens and Williams, Webb, or another English glassmaker with a form like that of the vase and pitcher in the ebay thread?)

Regarding the application of the yellow thingy, I agree it would be applied while the piece was being re-shaped while still hot from the mold.  I just thought it unlikely it was applied by another glass house.

Interesting patent - uranium and lead for red glass!  Also intriguing that it mentions manganese being used to counteract the effects of impurities, despite it being a colored glass.  I'd only heard of its use in colorless glass, but I suppose the green imparted by iron could detract from a nice red, too.

I also found it interesting that there were articles being written about "luminescence" of uranium glass as early as 1904.  Thank you all for sharing the information and references!

Kristi


"The most beautiful thing we can experience is the mysterious. It is the source of all true art and all science."

- Albert Einstein

 

Search
eBay.com
eBay.co.uk

Enter key words
Link to Glass Encyclopedia
Link to Glass Museum
Enter
key words
to search
Amazon.com