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Glass Identification - Post here for all ID requests => Glass Paperweights => Topic started by: Connie on July 09, 2006, 11:44:15 AM

Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: Connie on July 09, 2006, 11:44:15 AM
Quote from: in another thread
Cullets are especially prevelant in 19th-century paperweights and in many paperweights that are mainland China-made. You'll find them in Boston & Sandwich and New England Glass Company antiques. There are even classic French weights with cullets in them. I rarely see cullets in weights by most contemporaries. Never saw one in a Rosenfeld or a Stankard or a Trabucco or a Tarsitano or a Kaziun or a Perthshire or D'Albret or modern Baccarats or contemporary St. Louis.

Cullets look like little bits of "rock" or a rocklike substance floating in the glass dome, sometimes close to the canes or lampwork setting, sometimes simply drifting about the glass. They are actually very tiny touches of glassmaking material that didn't quite melt or fuse.

I don't think that "cullet" is the correct term for the inclusions in paperweights or any glass for that  matter.

Cullet is left over glass from the manufacturing process.  Like this

The specks in a glass piece are either described as frit or sand inclusions  or carbon inclusions if  black specks. The sand inclusions are undissolved silica in the molten glass.  The black specks are contaminants in the molten glass usually from flying ash or carbon desposits in the furnace.

Edited to correct typos due to extreme caffeine deficiency at time of posting. The IV is now connected and all is well  :wink:
Title: maybe, maybe not
Post by: wrightoutlook on July 09, 2006, 12:04:03 PM
In today's terminology, cullets are those flecks of flotsom floating in the glass dome. Sotheby's and Christies have long described the floating specks as cullets in their catalogues. As have Selman and even Mrs. Bergstrom in her book superb 1940s book on paperweights.

And usage on eBay - from those savvy about the thingies - also give credence to the use of the word cullet. Frankly, and I hope this doesn't offend anyone, these flecks or cullets actually look like tiny boogers. Lord, I can't believe I just typed that. I'm laughing too hard. Oh well, we're all adults here.
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: Connie on July 09, 2006, 12:19:10 PM
Oops! Well pardon me  8)  The use must be particular to paperweight collectors, of which I am not.

I have never seen cullet used in that context when discussing EAPG, Depression Glass, Elegant Glass of the Depression Era, etc.
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: Frank on July 09, 2006, 12:41:23 PM
Perhaps the mistake was originated in the Bergstrom book? Just another example of wrong in print becoming part of collectors terminology. It is really up to writers to correct such malapropisms, or at least a competent technical editor should be used.
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: Leni on July 09, 2006, 07:03:59 PM
Cullet is broken glass, added back into to the glass batch to be recyled.  

Frit is one of the ingredients of glass.  Sometimes a small piece of it doesn't completely melt and the bits can be left in the glass.  

I have never heard the little inclusions found in some paperweights (and other glass items) called 'cullet'.
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: KevinH on July 09, 2006, 08:52:16 PM
I am not going to agree or disagree right now on the "cullet" usage - maybe wrightoutlook is correct in the literary context mentioned.

However, in a 5-page message started in March 2005 in the Glass forum, I used the word "frit" in a certain context and invited comments about any errors I may have made. What said was:
From page 4 of,1179.45.html

[By KevH - in connection with flaws in paperweights]
2. Pieces of "Frit"

These appear as white or silvery irregular shaped lumps. Sometimes they can be quite large and easily noticeable from a distance. Others can hardly be seen. This is the result of crystalisation within the glass - another problem of temperature control or perhaps pieces from the ceramic pot getting mixed in the batch.

I have some weights with large pieces of "frit" and these fall into my category of "academically acceptable" even though they are visually imperfect. Depending on the current (or perceived) rarity of a design, I am sometimes prepared to pay reasonable sums for weights with a bit of "frit".

[By Adam D. - in response]
Warning - the following will cause acute boredom but, KevH, you asked for it!

Kev - Your "pieces of frit". Nothing wrong with the term, meaning unmelted raw material - usually bits of sand. However, "frit" was only for some reason used by Pilkingtons - all the rest of us called it "batch". I haven't a clue why, in hindsight I like the Pilks word better.

However, Kev, anything crystallising out from an originally clear glass (usually by holding it in a specific temperature range too long) is called "devitrification" (don't blame me). Generically, any foreign body in the glass, whether devit., unmelted batch/frit or bits of furnace are simply called "stones" or, in a few obscure places in NE England, "salts".

I did warn you!
So, from Adam D. we can add "Stones" and "Salts" to the list of terms. And I have certainly heard of, and used myself, "stones" in connection with 'lumps of stuff' in a paperweight dome'.

Title: cullets and frits
Post by: wrightoutlook on July 10, 2006, 12:49:14 AM
This is becoming a semantical argument.

A cullet IS a piece of broken glass that is re-fed into the system to be re-melted and to become part of the glass process again. Sometimes these bits of glass never completely disappear and stay in the system as a teeny tiny bit floating in the liquidy glass and end up within the completed paperweight dome.

If it's a cullet at the start of the remelting process, then when it fades and melts and becomes molten, some bits still remain and stay coarse and/or hard. These are surviving bits of glass that were cullets and when they survive and stay under the dome, they are still cullets - SURVIVING BITS OF GLASS.

A FRIT is now a specific type of paperweight - usually reading HOME SWEET HOME; GOD BLESS MOTHER; GOD BLESS AMERICA; I00F ELKS LODGE; FATHER KNOW BEST, GOD SAVE THE QUEEEN, etc.
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: Frank on July 10, 2006, 10:01:32 AM
Cullet is one of the oldest terms in glassmaking and is waste or scrap glass. Due to the difficulties of starting the melt of the glass metal cullet is often added to trigger the process. Some studios use only cullet to save on raw material costs.

French is Groisil
German is Scherben
Italian is Rottame di vetro
Czech is Strepy

Frit is the finely ground coloured glass used for colouring the melt or adding to a worked piece by marvering or other methods. This US glass supplier also uses the term so it is common to English speaking countries
Corning defines this further: Batch ingredients such as sand and alkali, which have been partially reacted by heating, but not completely melted. After cooling, frit is ground to a powder and melted. Fritting (or sintering) is the process of making frit.

Any other uses of these terms is likely to be erroneous and likely as not born in a poorly editted book for collectors. Other uses of these two words should be avoided to prevent further confusion.

Corning also provided the word for unwanted inclusions in glass as SCALE.

    An accidental inclusion in glass, consisting of corrosion products detached from the metal implements used to stir the batch or to form the object.


I have heard various other terms for this over the years, perhaps others would comment.

Kevin has also added the terms provided by Glass Technologist Adam Dodds "Stones"& "Salts".

Frit could also appear and of course will be a small piece of coloured glass in the wrong place.

Fritting (or sintering) is the process of making frit.
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: josordoni on July 10, 2006, 03:11:05 PM
Frank, what is the correct wording for those little tiny nibbles then?  I have seen it called fritting so long I just took it as correct, but will stop using that term if it is incorrect.

(please feel free to move this post if you don't think it fits here any more)
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: KevinH on July 10, 2006, 03:22:17 PM
:?: If "tiny nibbles" are evenly spaced and evenly sized around an edge then they are probably cutting done as part of the design. Otherwise they are simply small chips in the edge of the glass.

Perhaps people started to call them "frit" as it sounds a bit less negative than the basic truth which is that it is wear and tear damage.
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: KevinH on July 10, 2006, 04:02:28 PM
:D In connection with this, and a discussion on UV results, one of the blunders made by Sotheby's was the attribution of a weight as a rare Pantin Clover, aided by the fact that under uv it was said to fluoresce the same as other Pantin weights. The weight actually matched to other similar ones known (99% likely) to be by Paul Ysart and illustrated in the then available paperweight literature.

So yes, the "experts" do indeed make mistakes. In the case above, they were notified of the error and did the right thing by removing it from the sale.
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: Lustrousstone on July 10, 2006, 08:13:48 PM
The use of fritting for small nibbles probably comes from to fritter - to break into small pieces. But frit/fritting and fritter have completely different language roots.
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: aa on July 10, 2006, 10:04:38 PM
Quote from: "Lustrousstone"
The use of fritting for small nibbles probably comes from to fritter - to break into small pieces. But frit/fritting and fritter have completely different language roots.

That is an interesting theory. Generally frit is made by immersing hot glass in water. Rapid cooling and thermal shock causes the glass to harden and crumble.There are two ways this can be done.
1. Run molten glass from the furnace into a bucket of water.
2 Heat up broken glass (cullet) to about 500 degrees Celsius and drop into a bucket of water.

To a degree, Wrightoutlook is correct - this is a semantic argument. You can call these things whatever you like. Dealers and  auctioneers are welcome to make up as many terms as they like. But they should not be misleading. For example, a fleabite is a very sensible term for a concoidal fracture. It can be instantly understood by anyone from a novice to an expert. This is because it conjures up a visual image and the  term does not have any other meaning within glass making terminology.

To use the term "cullet" to describe a flaw in a paperweight, however, seems to me to be completely erroneous and I have never come across this. As stated clearly stated by others it has a completely different meaning in glass making terminology.

I'm 100% with my namesake, Adam D.
They're stones and at any given point  most of us would dearly love to know whether they are formed from unmelted or devitrified batch, or whether they are part of the pot or in a tank furnace, the refractory bricks that have gradually been attacked by the corrosive properties of glass. The only way to tell is send them off to the lab to be analysed. Rather expensive.

You can hardly see the small ones when the glass is hot, but if you do, you can pull them out with tweezers and shears and melt in the shear marks. Easier said than done, specially with big pieces.
Title: Cullet, Frit, Scale, Stones and Salts (Terminology)
Post by: Anne on July 10, 2006, 10:11:18 PM
Ahhh no, as from fritter it would be frittering not fritting.

Chambers' Dictionary gives this for frit/fritting (note the etymology):
frit noun the mixed materials for making glass, glazes for ceramics, etc. verb (fritted, fritting) to fuse (substances) partially in the process of making frit.
ETYMOLOGY: 17c: from French fritte, from Italian fritta, from Latin frigere to roast.

Fritter, on the other hand, comes from Old French freture and Latin fractura meaning to break (into fragments) as Christine said before.