Crushed Glass And Ceramics

[Colleen]

Hi Everyone,

 

Back in the 1970's I made a turtle statue into a lamp for a children's room. The turtle was about 14" high, sat up on it's hind legs and tail, had a hat on it's head and a big raised daisy flower on it tummy. I carved out the petals and leaves on the flower, then put masking tape on the inside of the cut-out areas. Then I poured yellow crushed glass crystals in each petal, and green ones in each leaf area. The studio owner then fired the turtle (he was already glazed with appropriate glaze before adding the crystals). The crystals fused to the sides of the cut-out area and the masking tape burned away. Unfortunately, the present studio owner had never heard of that technique, and I can't remember if the crushed glass was added before the turtle was glazed fired, or after. Nor do I know what temperature the glass was fired at, since it was done by the shop owner. The piece turned out great, though.

I now would like to repeate that technique. Does anyone know how to do it correctly?

Colleen

[GEP]

My experience with adding crushed glass on pottery is that it needs to be fired to cone 10 to melt reliably. It will sort-of melt at cone 6, but not completely. I've always glazed the pot, then added the glass, then glaze-fired it once. You might be able to add glass after a pot has been glaze-fired, but that would depend on the clay and the glazes and whether they can handle being re-fired. Good luck!

 

-Mea

[eburb]

hi Colleen, Did you find any more info on this - i would like to have a go at it but need help with the technical stuff. Any help would be great. Eden

[hansen]

crushed glass - cullet is of various compositions, and different kinds of glass fire at different temperatures. I've seen it added to sculpture clay as grog too.

h a n s e n

Hi Everyone,

 

Back in the 1970's I made a turtle statue into a lamp for a children's room. The turtle was about 14" high, sat up on it's hind legs and tail, had a hat on it's head and a big raised daisy flower on it tummy. I carved out the petals and leaves on the flower, then put masking tape on the inside of the cut-out areas. Then I poured yellow crushed glass crystals in each petal, and green ones in each leaf area. The studio owner then fired the turtle (he was already glazed with appropriate glaze before adding the crystals). The crystals fused to the sides of the cut-out area and the masking tape burned away. Unfortunately, the present studio owner had never heard of that technique, and I can't remember if the crushed glass was added before the turtle was glazed fired, or after. Nor do I know what temperature the glass was fired at, since it was done by the shop owner. The piece turned out great, though.

I now would like to repeate that technique. Does anyone know how to do it correctly?

Colleen

 

 

 

 

[Linnet]

hi Colleen, Did you find any more info on this - i would like to have a go at it but need help with the technical stuff. Any help would be great. Eden

 

 

I would be interested in techniques for this process also.

 

I have seen some amazing work with coloured glass melted in centre of dishes by placing various coloured glass onto the dish prior firing at cone 10.

I wonder if the glass could be placed into the clay after making the objuect and allowing a certain amount of drying,especially a vertical piece?

[Guest Sherman]

Colleen (and everyone),

 

I am a firm believer in testing. If you're firing flat (or at least horizontal), it seems you simply need to test for the temperature at which your chosen glass will melt and then conduct some basic tests. Do a simple fusion button test by firing some ground glass (or chunks of it) in a small pile to different temperatures to see when it melts best. Be sure to put it in a small test bowl so it doesn't ruin a shelf.

 

Most container glass and window glass is soda-lime glass, so called because it uses sodium as a flux and has calcium to stiffen it a bit and help it to stand up to the rapid mechanical mold production. It has a high coefficient of expansion, which is why it crazes like crazy when it's thick.

 

I think if you want to experiment with glass on a vertical surface in a kiln, the amount of glass you use will matter quite a bit; the more glass, the more likely it will run off the pot. Attached is an image of work by Mark Hewitt. The little diamond shapes are the glass pieces he impresses into the surface, and the large areas of lighter surface around and below those diamonds are how far the glass traveled over the surface after melting. Very nice, very elegant, but I'm sure he did a lot fo testing to figure out just how much was enough---and not too much.

 

Dont' be afraid---but be smart and careful. Happy testing!

 

Sherman

[spinningearthelements]

Colleen (and everyone),

 

I am a firm believer in testing. If you're firing flat (or at least horizontal), it seems you simply need to test for the temperature at which your chosen glass will melt and then conduct some basic tests. Do a simple fusion button test by firing some ground glass (or chunks of it) in a small pile to different temperatures to see when it melts best. Be sure to put it in a small test bowl so it doesn't ruin a shelf.

 

Most container glass and window glass is soda-lime glass, so called because it uses sodium as a flux and has calcium to stiffen it a bit and help it to stand up to the rapid mechanical mold production. It has a high coefficient of expansion, which is why it crazes like crazy when it's thick.

 

I think if you want to experiment with glass on a vertical surface in a kiln, the amount of glass you use will matter quite a bit; the more glass, the more likely it will run off the pot. Attached is an image of work by Mark Hewitt. The little diamond shapes are the glass pieces he impresses into the surface, and the large areas of lighter surface around and below those diamonds are how far the glass traveled over the surface after melting. Very nice, very elegant, but I'm sure he did a lot fo testing to figure out just how much was enough---and not too much.

 

Dont' be afraid---but be smart and careful. Happy testing!

 

Sherman

 

[spinningearthelements]

I saw this thread and thought I'd share some info, although I apologize for not having anything technical.

 

We've (I teach HS ceramics) done decorative pieces with melted glass beads (the kind you typically see in flower vases). Since we're only firing to Cone 5, we're not getting a full melt and the glass is not thoroughly bonded with the pieces. I've found that the clear glass makes a nice crackle on forms with a medium to light colored glaze. I see some excellent advice above about testing to see how much the glass bonds with the glaze.

 

For interesting FYI, look up Steven Forbes-deSoule's Raku work. He has melted stained glass at the top of some of his really rounded forms in a Raku fire. The temps of the firings he was doing in our workshop ranged from 1800 to 2000. ( :

 

Happy experimenting!

[Linnet]

Yes I beleive in testing, experimenting and each time my new piece arrives from the kiln, I alway have a question 'What if..." then I re test and test again. so much so that 70% of my work is testing/test pieces. So it is nice to have everyones experience and input at hand here.

Thank you for that.

[OOF!]

Here's a piece by Jay Strommen using glass.

vector_sculpture

He has more at his web site, jaystrommen.com. Look at his vector sculptures, and others.

He teaches at Lillstreet in Chicago, and it took him many tries to get these to work.

Very, very talented guy, and can make the wheel sit up and beg if that's what he wants it to do.