Topic: Anybody heard of skeleton molds?

[krsilber]

Ach, what a tease!  I'm interested to see how it went and what you found. 

I've ordered the book History of Glassforming and it should arrive any day.  That's the one I saw the funky mold in.  Alas, I guess I can't show a photo of the page on the board here, but maybe I can trace it.

(What's Ali Pally?!)

...that made me go check my mail, and it came!

[krsilber]

Here we have it...Cummings calls it a distorting mould.  "A distorting mould operated by an outside ring which is pushed up and down to open and close the brass arms.  Unlike bolivers that are designed to shape the rim area, this type of device was used to partially shape the original bubble by distorting its surface into undulations that were reminiscent of rock crystal carvings."  There's also an original glassmaker's drawing of a decanter with bosses shown as an example of the type of thing it was used for.

Sorry if the tracing looks sloppy.  It's from a 2" image.  The mould is pictured here open.

GREAT book, by the way!

[Patrick]

Hi,
Back from the Fair and had a good morning buying four nice Whitefriars pieces.
As I said yesterday was a very long day and I bought nothing , but did bid for a short while on Lot 327 . Not 100% sure but I think the hammer fell at 135.00 , it was stunningly beautiful but I don't collect cut glass . The buyer of this piece went on to acquire most, if not all of the ' Rock Crystal '. My friend was the under bidder on 3 of the lots he won and we suspect he would have bought them at any price !
Lot 165 was also stunning and in great condition. The 'optic' areas were as I suspected only windows being formed by clever cutting of the main body. I have attached an image that I think shows them clearly.
Finally ' Aly Pally ' is a slang expression for  Alexandra Palace ............. http://www.alexandrapalace.com/
For many years there was a monthly antiques fair held that was great for buying glass with many more stalls than todays fair. For the last year there has been one and this was a first time in a new series.
All best wishes,
 Patrick.

[krsilber]

I agree, in this case it looks like the ovals may be simply areas that weren't cut.  But that doesn't mean they're all like that, of course.  Thanks for the photos!  Makes me so envious; I would have loved to see glass like that in person.

Boy, I'd like to ask a few questions of the buyer of the rock crystal pieces!

[krsilber]

I was browsing Sinclaire and Spillman's The Complete Cut and Engraved Glass of Corning just now.  There's a photo of The Pitcher from the OP on a page I've referred to many times, but only now has it gotten through to me what the caption says:  "Cut and stone-engraved Steuben Glass Works ewer, ca. 1910, used a molded blank that imitated the cut medallions of costlier rock-crystal designs."

I also found out that Paul Gardner, the author who said the pitcher was made using a skeleton mold, was Frederick Carder's assistant for 10 years.  So it seems like he'd be in a pretty good position to know how it was made.

The other day I ran across a tracing I made of the mold pictured in Cummings's History of Glassforming - same mold as the other tracing I posted, but this time in a closed position.  I figure I went to the work of tracing it, may as well post it for posterity.

[Frank]

Good detective work.

[Sid]

Hello:

Have a look at this webpage.  There are many different devices for shaping hot glass including the examples traced by Kristi.  They can be seen in figures 21 and 22. Very interesting!

http://aurora.sunderland.ac.uk/gateway_to_glass/htmlsite/h_journal_refereed_19centuryglass.htm

Have a good look around the rest of the site as well.

[krsilber]

Excellent site!  Thanks, Sid.  Keith Cummings is the author of the book I traced those from...all that work, and it was on the internet all the time!

[Frank]

Siemens patented a skeleton mould for moulding bottles and it states, either the article or the mould is rotated during moulding. It does not state the purpose of a mould that has air holes, presumably lower manufacture costs and faster cooling. It states skeleton moulds may be built up of bars.

[krsilber]

When was this?  Do you have a copy of the patent, or a link?  I'd like to see it.  My guess is it's not related to the moulds discussed here previously.

The object/mould would be rotated presumably to avoid the texture given the surface of glass by metal moulds, just as an object is rotated in a turn/paste mould.  If the interior of the mould doesn't have a water-retaining surface, maybe the holes inject a bit of air to keep the glass away from the metal?  Or they're simply for cooling the mold, as molds used continuously tend to get too hot.  I read somewhere the other day about molds that had air circulating through them to keep them cool.

I wonder what it means that they were built up of bars.