Friday, December 21, 2012

Slumped glass

I was trying to find a ceramic project that involved clay, but didn't end with the clay being the final result.  Luckily a few years ago I took a glass fusing class and decided to try that again.  A few years ago I tried this project and we had horrible results, but I was willing to try again. And thanks to the internet I had more resources to figure out my first mistakes.

We started with a flat piece of glass and some small scrapes of glass that the students used to create their designs.  Using elmers glue, we attached the small pieces of glass to the large background piece.  It only takes a tiny smear of elmers to get the two to stick together.   Then I tack fused these pieces together in the kiln.  I fired it to about 1380 degrees.

After our plates came out of the kiln we then created a mold to slump the glass into with our clay.  Most of the kids made a simple square box, but some of the lessons I learned from the first time doing this project were this.  Make sure that the top edges of the box are flat and even and more narrow then the bottom part of the box.  Basically you want the walls to be a triangle shape so that the glass folds over but not under the clay.

I also learned from my mistakes about firing the clay.  Basically do not pre-fire the clay.  Let it air dry, put the glass on top and then bake it in the kiln at the glass slumping temps.  The slumping temp I used was 1230 degrees.  The reason for not pre-firing the clay is so that if the glass does happen to get stuck we can then chip away the clay and hopefully free the glass without breaking it.  If you pre-fire the clay it is so hard that if your glass sticks you are just in trouble.

If everything works right you then end up with these unique glass bowls or little dishes in our case.  They can't hold a lot of anything, but they are basically for decoration.

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Connor F.
This one was photographed still in it's clay mold.

Kelsey C.
You can still see the heart mold under the clear glass.


  1. These are great! Congratulations, and thanks for sharing them :) Elizabeth

  2. These are awesome! Do you typically put anything like kiln paper or kiln wash between clay and glass? I'm wondering if the clay( low fire?) adheres to the glass at all. Thank you.

  3. If you are nervous you can kiln wash the clay piece, but as long as it is not a weird shape I have never had one stick for more than a second or two. Just make sure there are no holes for the glass to find its way into.