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Author Topic: Glass Technology - The Pontil or Punty  (Read 2864 times)

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Offline Frank

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Glass Technology - The Pontil or Punty
« on: March 07, 2008, 09:52:35 AM »
This topic is purely about the different forms of pontil, the tool used to hold the glass for finishing work after removal from the blowing iron.

Collectors refer frequently to the lump of glass or snapping scar as the pontil but that is inaccurate, Hodkin & Cousen (will be my primary source in this post) name the lump of glass, parison,  used to connect the pontil to the blown globe as "Bull's Eye", a better name and presumably derived from the result on blown window glass.

For bottles the pontil consists of a split iron cylinder attached to the end of an iron rod. The fixed diameter being set to the size of the bottle to be finished. Leaving no Bulls Eye. Prior to full automation the Punty Feeder was a machine that made the gather on a pontil rod and fed this gather into a blowing machine.

Fixed sized gripping pontils are fine for standard size production. For more flexibility a sprung arrangement would be used and some would have prongs rather than a split cylinder, some gripped the outer edge of the base but others were smaller and typically left a mark of 3, 4 or more indentations.

The pontil rod that leaves the snap-off scar or a raised bull's eye
(http://www.ysartglass.com/BaseLabel/Baseimage/MBase01a3.jpg)
use a small piece of glass gathered to the end of the pontil to create the join to the parison while it is still on the blowing pipe. After finished the object is snapped off and the remaining bull's eye has to be finished of by grinding.
(http://www.ysartglass.com/BaseLabel/Baseimage/MBase06a2.jpg)
n.b. the pit in this example was caused by the break off.

And maybe polishing of completely removing any trace
(http://www.ysartglass.com/BaseLabel/Baseimage/MBase07a.jpg)

Terminology varies from country to country and glassworks to glassworks and hopefully other will add (or correct any errors above) more information.
Frank A.
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Offline Ivo

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Re: Glass Technology - The Pontil or Punty
« Reply #1 on: March 07, 2008, 10:27:20 AM »
Pontil mark is still the proper designation for anything snapped off.  Most people abbreviate it to pontil which is technically incorrect but everybody knows what you're on anyway.
I would not recommend the usage of the word "bull's eye" unless you mean a centrifugal window pane.
Ivo
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Offline Leni

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Re: Glass Technology - The Pontil or Punty
« Reply #2 on: March 07, 2008, 11:36:41 AM »
As I understand it, the word 'pontil' is French, from the word 'pont' meaning 'bridge', and should therefore be pronounced 'pontee'.  English glassblowers, hearing this word, spelled it as they heard it and it became 'punty'.   
Leni


Offline johnphilip

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Re: Glass Technology - The Pontil or Punty
« Reply #3 on: March 07, 2008, 02:35:04 PM »
Then you have the Italian (Venetian) multi point pontil.three,four and five point,if my memory is still intact.JPH.


Offline Adam

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Re: Glass Technology - The Pontil or Punty
« Reply #4 on: March 07, 2008, 09:55:25 PM »
Frank - You are lucky to have a copy of Hodkin & Cousen.  When I was a student it would have been our bible had it not been already (all right, I admit it, this was 1946-49!) well out of print.  I seem to remember that there was one tatty copy in the library.

I'm a bit worried about the word parison in the context of this thread.  In automatic bottle production (I have no first hand experience of the hand-blown methods) a "parison" is, or was,  the exact UK equivalent of the US "blank".  This is the first forming stage (in the parison or blank mould) before transfer to the blow mould which is the shape of the finished article.  No doubt these terms are carried forward from the hand-blown days but as to exactly how I must pass.

Adam D.


Offline Frank

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Re: Glass Technology - The Pontil or Punty
« Reply #5 on: March 07, 2008, 10:36:15 PM »
I was to, but decided to use it in the way it is used in the book. It was of course written a long time ago.
Frank A.
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Offline jsmeasell

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Re: Glass Technology - The Pontil or Punty
« Reply #6 on: March 08, 2008, 12:11:30 AM »
At Fenton Art Glass, items are either "snapped up" (using the tool that is called a "snap" in the US and, I believe, a "gadget" in the UK) or "stuck up" (this involves a bit of hot glass being gathered on a punty rod and then that hot glass is brought to the outside bottom of the item and it "sticks" to secure the item for further warming-in, etc. After a stuck up item has been reshaped, finished, etc., it must be "cracked off" the punty rod and quickly taken to the lehr. We use a hand-held torch to soften the punty mark right after cracking off, and this method is greatly superior to the old way of grind/polish when the glass has been annealed.

There are many different kinds of snaps, but that is a discussion for another time.
James Measell, Historian
Fenton Art Glass Co.


Offline krsilber

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Re: Glass Technology - The Pontil or Punty
« Reply #7 on: March 08, 2008, 02:36:18 AM »
This seems like a topic with a lot of potential for semantic differences stemming from point of origin - US or UK, primarily.

Interesting to hear James talk about Fenton's pontils, when I (who knows very little about Fenton, sorry James) have heard that Fenton almost never has them!  I've heard people many time exclude Fenton as a candidate for ID because an item has a pontil mark.

Definitions of some of these terms according to my understanding:
In the US "pontil" (pontil mark/scar) refers to the point of attachment, while "punty" refers to the rod.  A parison is the small blob of glass just beginning to be blown, before it is worked into final shape.  "Blank" is a little harder to define.  The most narrowest definition I've heard is, a cooled item that is intended to be decorated by etching, cutting, enameling, etc.  Since many items may end up undecorated, though, it is often used less specifically to refer to any item in a pattern (I'm thinking here mostly about American Elegant and Depression glass, e.g. Heisey, Cambridge, etc.).  It's also a very common term in rich cut (miter cut, what I call the "sparkly stuff") glass circles, but is used there to refer to a pre-cut glass item, or the shape it would have been before cutting.  In the case of figured blanks, it may already have a pattern molded into it that will be further elaborated by cutting.

So a snap=a gadget!  Huh!  Is the term "marie" used in the UK?

This site has an excellent explanation of different types of pontil scars:
http://www.sha.org/bottle/pontil_scars.htm
and its parent page has lots more great info and links, geared toward bottle making, but applicable to other glass as well:
http://www.sha.org/bottle/glassmaking.htm
(I notice they call it a "pontil rod," rather than "punty rod")
Kristi


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Offline Frank

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Re: Glass Technology - The Pontil or Punty
« Reply #8 on: March 08, 2008, 10:30:52 AM »
The potential for semantic differences is innate to GT issue, not only by country but by glassworks and industry sector too. Which is why having an open thread on the topics is so useful as we get input from so many sources and get to learn something about them. Plus, of course, collectors have brought a number of terms into use themselves.

More subtle that the language is that there are also differences in the approach to the same issues.
Frank A.
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Offline Leni

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Re: Glass Technology - The Pontil or Punty
« Reply #9 on: March 08, 2008, 12:01:11 PM »
According to Allan Scott, the glass making tools called 'Pucellas' - sometimes known as Jacks - have always been called 'Priscillas' at Caithness!   In fact, in the Caithness millefiori paperweight 'The Glassmaker', which shows the glassmakers' tools in picture canes, the description card actually refers to these as 'Priscillas'!  ;D
Leni

 

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