I had always understood that Pate de Verre in a manner similar to Wikipedia definition:

Pate de verre is another form of kiln casting and literally translated means glass paste.[9][10] In this process, finely crushed glass is mixed with a binding material, such as a mixture of gum arabic and water, and often with colourants and enamels. The resultant paste is applied to the inner surface of a negative mould forming a coating. After the coated mould is fired at the appropriate temperature the glass is fused creating a hollow object that can have thick or thin walls depending on the thickness of the pate de verre layers.”

However, Marie-Alice Skaper, Development Manager, CERFAV (idverre.net) checked in and had the following to say:

“in France,when we use the words ‘pâte de verre’, it’s not referring to the Egyptians’ technique… You’re right, pâte de verre was originally painting a paste into a mould. But nowadays, in France, this painting is called stamping  “estampage” : you mix glass powder with gum arabic for example, and put it by hand with a brush into the mould), and can be used in the pâte de verre process if needed, but it’s optional. What we call pâte de verre in France is certainly what you call ‘kiln casting’. We put cold crushed glass in the mould (powder or little piece) without anything else (no binder), and we fire it in the kiln to about 800°C. That’s this process that everybody in France calls pâte de verre.”

Marie-Alice Skaper provided some more detail:

estampage de verre is really the action of manually putting the glass paste into the mould with a brush. I would say that it refers to the external layer, but not to the final object itself. It’s a way of decoration.

In France, “pâte de verre” is the process of putting together in a mould some pieces of cold solid glass, whatever the sizes of the pieces (powder, smaller or bigger particles), and heating until you obtain your final object. There are 3 different practices possible that we call “pâte de verre” :

– use only of glass powder, mixed to be a paste. Ex : photo of Henri Cross object. This is the original method, and I think that this is the only thing that you call pâte de verre in America.

– use of the glass paste put by hand in some parts of the mould, then the mould is filled with cullet (pieces of cold crushed glass) and fired. Ex : photo of Walter : the salamander is made with glass paste deposed by hand (“estampage”), and then the rest of the piece is made by addition of cullet.

– use only of cullet (pieces of cold crushed glass). Ex : our little house.

In fact, when you use powder, you have this opaque effect. The bigger the glass pieces used will be, the more transparent the final object will be.

This conversation is interesting, because it make me realize that you 3DP in glass could maybe have several goals :

– sure it could be used for rapid prototyping. That’s what we can test with the little house, and see how to improve if needed.

– maybe it could be used for decoration too. I mean that maybe we can imagine to print the external layer of an object, and then make a plaster mould around, fill it with glass cullet (as our pate de verre process) and fire in a kiln. Can you imagine to use powder of different colors at once in your printer, print the external layer of Henri Cros object I have attached for example, and fill the printing with transparent cullet to obtain the same object? The decoration would be then more precise than made by hand…

Do you think it’s a total ‘delirium’? :-)”

{No, not at all.  This is exactly why we need this type of open exchange!}

Anyone else care to come forth?

24 Comments on Pate de Verre (or not) … It’s complicated!!!

  1. I’m a pate de verre artist and would love to work with you on your project. (I’m also a geek–I ran computer labs and computer magazines, including BYTE Magazine) for years. I originally learned PdV in France, came back to the US and have been developing new techniques with it ever since.

    I spend quite a bit of time discussing and illustrating PdV technique on my blog. At present I’m using PdV layering techniques to simulate human skin/flesh for portrait work. It’s quite involved–there are as many as 20 layers in a portrait, categorized in four groups: Surface (color/detail layers), overtones (selective color enrichment), undertones (primarily light management), filler.

    I’ve been looking into building my own 3D printing system for modeling and mold-making, and wondering if it’s possible to do the same with frit (crushed glass). Your examples are intriguing, would love to discuss. The URL I’ve given you is a direct link to an article I wrote on packing glass for a particular sculpture.

    Thanks–

    –cynthia

  2. I’m a pate de verre artist and would love to work with you on your project. (I’m also a geek–I ran computer labs and computer magazines, including BYTE Magazine) for years. I originally learned PdV in France, came back to the US and have been developing new techniques with it ever since.

    I spend quite a bit of time discussing and illustrating PdV technique on my blog. At present I’m using PdV layering techniques to simulate human skin/flesh for portrait work. It’s quite involved–there are as many as 20 layers in a portrait, categorized in four groups: Surface (color/detail layers), overtones (selective color enrichment), undertones (primarily light management), filler.

    I’ve been looking into building my own 3D printing system for modeling and mold-making, and wondering if it’s possible to do the same with frit (crushed glass). Your examples are intriguing, would love to discuss. The URL I’ve given you is a direct link to an article I wrote on packing glass for a particular sculpture.

    Thanks–

    –cynthia

  3. BTW, I’d take issue with Mme Skaper’s characterisation of estampage vs. pate de verre. There is a certain amount of confusion as to the exact definition of pate de verre, thanks to its origins. The use (or non-use) of binders can be argued–some insist that the term, “paste of glass” mandates mixing glass some kind of liquid/binder to form the “pate;” others disagree and say the term refers to the softening glass in the mold. However, I’ve worked with several pate de verre artists in France; all consider the particle size crucial in defining pate de verre; if the particles are too big, it’s not pate de verre. So, obviously, not “everyone” agrees with Ms. Skaper’s definition. Certainly US pate de verre artists wouldn’t.

    All pate de verre is kilncast glass; not all kilncast glass is pate de verre. One of the defining characteristics of pate de verre is its jade- or alabaster-like translucency. If the particles of glass used (at least on the surface) were much bigger than grains of sand, the piece would not trap the requisite number of tiny, light-reflecting bubbles for pate de verre. The piece would be too transparent, the bubbles too large, and most pate de verre experts would not consider it to be pate de verre.

    Generally speaking, pate de verre is distinguished from regular kilncast glass in three ways:
    1) Form of glass (small particles or powder)
    2) Where you put the glass (directly in the mold–the glass will compact, but should not move)
    3) How you deal with bubbles (unlike kilncasters, who go to great lengths to avoid bubble formation in glass, PdV artists encourage the formation of microscopic bubbles to give PdV its signature look and feel)

    If Mme. Skaper’s “little house” is created only with cullet, i.e., walnut-sized or larger pieces of glass, it wouldn’t be considered pate de verre by most aficionados. I would agree that her other two examples would be pate de verre.

    Hope that helps.

  4. BTW, I’d take issue with Mme Skaper’s characterisation of estampage vs. pate de verre. There is a certain amount of confusion as to the exact definition of pate de verre, thanks to its origins. The use (or non-use) of binders can be argued–some insist that the term, “paste of glass” mandates mixing glass some kind of liquid/binder to form the “pate;” others disagree and say the term refers to the softening glass in the mold. However, I’ve worked with several pate de verre artists in France; all consider the particle size crucial in defining pate de verre; if the particles are too big, it’s not pate de verre. So, obviously, not “everyone” agrees with Ms. Skaper’s definition. Certainly US pate de verre artists wouldn’t.

    All pate de verre is kilncast glass; not all kilncast glass is pate de verre. One of the defining characteristics of pate de verre is its jade- or alabaster-like translucency. If the particles of glass used (at least on the surface) were much bigger than grains of sand, the piece would not trap the requisite number of tiny, light-reflecting bubbles for pate de verre. The piece would be too transparent, the bubbles too large, and most pate de verre experts would not consider it to be pate de verre.

    Generally speaking, pate de verre is distinguished from regular kilncast glass in three ways:
    1) Form of glass (small particles or powder)
    2) Where you put the glass (directly in the mold–the glass will compact, but should not move)
    3) How you deal with bubbles (unlike kilncasters, who go to great lengths to avoid bubble formation in glass, PdV artists encourage the formation of microscopic bubbles to give PdV its signature look and feel)

    If Mme. Skaper’s “little house” is created only with cullet, i.e., walnut-sized or larger pieces of glass, it wouldn’t be considered pate de verre by most aficionados. I would agree that her other two examples would be pate de verre.

    Hope that helps.

  5. admin says:

    Cynthia, I tend to agree with your points (as your ideas agree with the way that I learned the concepts and materials). However, the best part of this interchange is that groups of people are exchanging ideas (We could ask for better). Thanks for checking in and let’s make something cool.

  6. admin says:

    Cynthia, I tend to agree with your points (as your ideas agree with the way that I learned the concepts and materials). However, the best part of this interchange is that groups of people are exchanging ideas (We could ask for better). Thanks for checking in and let’s make something cool.

  7. Polprav says:

    Hello from Russia!
    Can I quote a post in your blog with the link to you?

  8. Polprav says:

    Hello from Russia!
    Can I quote a post in your blog with the link to you?

  9. admin says:

    Polprav, sure. One of the important functions of this site is to bring people together and get them sharing ideas.

  10. admin says:

    Polprav, sure. One of the important functions of this site is to bring people together and get them sharing ideas.

  11. Marie-Alice Skaper says:

    Hello from France!
    I’m sorry if I hurt Cynthia, but as Mark said, this exchange is very interested because it allows to understand that words not always mean the same to everybody… I think that the main difference between Cynthia’s definition and mine is that she uses the words “pâte de verre” to name the final object, and I use the words “pâte de verre” to name the process itself. But at the end we say the same: powder gives opaque effect, the bigger the glass pieces will be the more transparent the final object will be.

    A lot of famous French artists come in our school to teach their arts, and they often don’t agree even between them on this point! Cynthia and some of them say that man can not use the words “pâte de verre” if the glass pellets used are too big… You certainly know the French luxury company Daum (www.daum.fr). Everybody in France will tell you that they produce articles made of “pâte de verre” (even “pâte de cristal”), and yet they often use big pieces of glass in their process! They choose the size depending on the effect they want to obtain… That’s why in our school we prefer to use the words “pâte de verre” for the process more than for the final object. Then ‘almost’ everybody is ok 🙂

    Please have a look at http://www.e-vitra.eu : we have worked with several glass schools in Europe to create this training tool totally free of charge. You will find there the definition of the “pâte de verre” process and the related training (video and written documents). The example used in the training is a little devil created with crushed glass of several sizes (small and bigger).

    I hope it helps to understand what I previously said (even if my English is not perfect, sorry).
    Has someone else a point of view about this exchange?

  12. Marie-Alice Skaper says:

    Hello from France!
    I’m sorry if I hurt Cynthia, but as Mark said, this exchange is very interested because it allows to understand that words not always mean the same to everybody… I think that the main difference between Cynthia’s definition and mine is that she uses the words “pâte de verre” to name the final object, and I use the words “pâte de verre” to name the process itself. But at the end we say the same: powder gives opaque effect, the bigger the glass pieces will be the more transparent the final object will be.

    A lot of famous French artists come in our school to teach their arts, and they often don’t agree even between them on this point! Cynthia and some of them say that man can not use the words “pâte de verre” if the glass pellets used are too big… You certainly know the French luxury company Daum (www.daum.fr). Everybody in France will tell you that they produce articles made of “pâte de verre” (even “pâte de cristal”), and yet they often use big pieces of glass in their process! They choose the size depending on the effect they want to obtain… That’s why in our school we prefer to use the words “pâte de verre” for the process more than for the final object. Then ‘almost’ everybody is ok 🙂

    Please have a look at http://www.e-vitra.eu : we have worked with several glass schools in Europe to create this training tool totally free of charge. You will find there the definition of the “pâte de verre” process and the related training (video and written documents). The example used in the training is a little devil created with crushed glass of several sizes (small and bigger).

    I hope it helps to understand what I previously said (even if my English is not perfect, sorry).
    Has someone else a point of view about this exchange?

  13. admin says:

    Marie, at this point, I would like us to keeping the discussion going and to make beautiful glass. 3DPglass is a new technique that makes new things possible.

    What about Egyptian Paste?

  14. admin says:

    Marie, at this point, I would like us to keeping the discussion going and to make beautiful glass. 3DPglass is a new technique that makes new things possible.

    What about Egyptian Paste?

  15. Robin Elsey says:

    Following a good read of Cumming’s book I was inspired to try Pate de Verre or at least a derivative of it for jewellery items.
    I have a Roland Modella NC machine which I used to make wax masters from which I cast silicone rubber moulds. To make my quite small pieces (usually not larger than 60mm X 60mm) X 9mm thick) I use Bullseye CoE 90 fine glass frit and powder mixed with about 15% by volume PVA adhesive. This is then converted into a stiff paste using deionised water. I pack the mould using dental tools, allow the surface to dry then dry in a domestic oven at 130 deg. C for 60 to 90 minutes. After cooling, the object is removed from the mould and then cleaned up. In this unfired state the object is quite durable. Once satisfied with the item I fire to approx. 710 deg. C at which temperature fusing takes place accompanied by a welcome shiny surface and a not so welcome shrinkage which seems to vary between 20% and 25% depending on the size of frit or powder.
    After a little searching I have now found suppliers of metal lustres and vitreous enamels which fuse at between 550 and 600 deg. C. I have yet to test them.
    I doubt that all this pushes the art of PdeV into untrodden paths but may interest new entrants into this fascinating bye-way of glass working. Have a go!
    Robin Elsey

    • admin says:

      Robin, thanks for checking in. From what I hear from others and our own work, you shrinkage numbers are right in line. If you use finer frit, you may see higher shrink and you will have less transparency. Try firing at a lower temp and you should see lower shrinkage (but less sintering/fusing). All of the parameters are trade-offs to your final result.

  16. Robin Elsey says:

    Following a good read of Cumming’s book I was inspired to try Pate de Verre or at least a derivative of it for jewellery items.
    I have a Roland Modella NC machine which I used to make wax masters from which I cast silicone rubber moulds. To make my quite small pieces (usually not larger than 60mm X 60mm) X 9mm thick) I use Bullseye CoE 90 fine glass frit and powder mixed with about 15% by volume PVA adhesive. This is then converted into a stiff paste using deionised water. I pack the mould using dental tools, allow the surface to dry then dry in a domestic oven at 130 deg. C for 60 to 90 minutes. After cooling, the object is removed from the mould and then cleaned up. In this unfired state the object is quite durable. Once satisfied with the item I fire to approx. 710 deg. C at which temperature fusing takes place accompanied by a welcome shiny surface and a not so welcome shrinkage which seems to vary between 20% and 25% depending on the size of frit or powder.
    After a little searching I have now found suppliers of metal lustres and vitreous enamels which fuse at between 550 and 600 deg. C. I have yet to test them.
    I doubt that all this pushes the art of PdeV into untrodden paths but may interest new entrants into this fascinating bye-way of glass working. Have a go!
    Robin Elsey

    • admin says:

      Robin, thanks for checking in. From what I hear from others and our own work, you shrinkage numbers are right in line. If you use finer frit, you may see higher shrink and you will have less transparency. Try firing at a lower temp and you should see lower shrinkage (but less sintering/fusing). All of the parameters are trade-offs to your final result.

  17. Robin Elsey says:

    Hi Admin!
    Thanks for your response to my opening comment. Since writing it I’ve made (and am making) some interesting ‘discoveries’. As I’ve no commercial interests at stake are you interested if I bother you with them? Again, nothing that old hands don’t know already but newer entrants might find interesting. There don’t seem many books on the subject that give stage by stage details of the processes and detailed quirks of the specific materials being used.
    I have tried slightly lower temperatures but fine frits don’t fuse smoothly – but OK for powders.
    Thanks again,
    Robin Elsey

    • admin says:

      Robin, the fused glass art community is not always happy with what I share. The protection of an artists intellectual property (secret processes) is often extremely important to protecting ones ability to make money. If you keep notes and run a large number of experiments, it is often possible to re-discover them (don’t forget to look online too). The other direction that you might take is to take a course offered by a PDV artist or school. Please keep sharing your progress. If you send pictures, I will try to post them. Cheers.

  18. Robin Elsey says:

    Hi Admin!
    Thanks for your response to my opening comment. Since writing it I’ve made (and am making) some interesting ‘discoveries’. As I’ve no commercial interests at stake are you interested if I bother you with them? Again, nothing that old hands don’t know already but newer entrants might find interesting. There don’t seem many books on the subject that give stage by stage details of the processes and detailed quirks of the specific materials being used.
    I have tried slightly lower temperatures but fine frits don’t fuse smoothly – but OK for powders.
    Thanks again,
    Robin Elsey

    • admin says:

      Robin, the fused glass art community is not always happy with what I share. The protection of an artists intellectual property (secret processes) is often extremely important to protecting ones ability to make money. If you keep notes and run a large number of experiments, it is often possible to re-discover them (don’t forget to look online too). The other direction that you might take is to take a course offered by a PDV artist or school. Please keep sharing your progress. If you send pictures, I will try to post them. Cheers.

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