Tuesday, May 17, 2011

Recycled Glass Results

The bowl above is the test result for melting recycled glass in this bisque firing to cone 04. In the past I tried melting beach glass in a small pinch bowl to cone 6 over a tenmoku glaze with success.

Next time I melted the same beach glass in a pinched moon bowl over clear glaze to cone 6 and that was successful as well.

In that same firing I also tried melting some green recycled glass over tenmoku with variable results. I also melted green and red glass over various glazes and those colors of glass turned blue or dark, almost black (no photo). And I melted the same recycled glass in terra cotta colored clay bowls without glaze and the glass was not attractive with that clay at all. The white clay shows the glass colors much better.

I determined glass placed over a glaze affects the color and even the slightest variation in glass color can result in a great variation of color when it is melted. For example one piece of red glass turned almost black. I also reasoned some glass might need to melt at a lower temperature to retain it's color. If you have experience melting glass over glazes, please feel free to give me advise on temperatures and types of glass you've used.

So this time I tried melting the same recycled glass samples in a bowl without glaze to cone 04 in this bisque load and I got some great results. Most of the green, red, and turquoise glass retained their colors nicely. I'm loving these glass color results and my mind is racing on how I'll use these with my flowers. The amber glass has variable results and the clear glass well it's clear, not sure how I will use the clear but it might be interesting over a darker glaze.

In this bisque firing I was also going to try firing some square headed nails to see if they held their shape, but at the last minute I decided not to risk the metal nails in the firing. Gary said the metal might have impurities and might sputter inside the kiln. Rather than risk that possibility, I will fire the square headed nails in a covered dish next chance I get in case the metal does sputter at bisque or glaze temperatures.

I'm glazing the bisque load now and it's taking me forever. Since the kiln was full of small items, there's a lot of glazing to do. I'm hoping I can fire tonight. Stay tuned for the Florida clay slip results and some finshed work in a few days.

Creative Commons License
Recycled Glass Results by Linda Starr is licensed under a Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License.
Based on a work at bluestarrgallery.blogspot.com.


  1. Those square headed nails may contain lead which could transfer in the heat to other pieces. Better to have left them out of the kiln.

  2. Hi Lori, thanks, good point, I guess I'll forget about the nails, didn't even think about that.

  3. like Lori, i always have lead concerns, not only with pottery but with bringing old painted wood into my home or studio. exploring melting glass has been on my mind for many year but i never seem to get around to trying it, i like your results and just may give it a go! thanks for sharing.

  4. I really love that you are so willing to experiment. It leads to so many interesting results. I hope you have a great day. Blessings...Mary

  5. I love the results of the blue glass in the white bowl! Lovely.

  6. A timely post for me, Linda. I fooled around with glass a tiny bit while at the desert studio this winter, but I didn't have much to work with except those little half marble thingies that you use in vases and mosaics. Here at home I have different colors of sea glass (some real and some "manufactured" or tumbled) but I won't use the real pieces. I also have two big boxes of various color and texture stained glass that I picked up at a garage sale for $5. I've been picking through it and thinking about how I want to use it with my clay.

    I'm following your experiments with great interest and will share my results as soon as I begin. The electrician was here last week to wire the circuit for my kiln and yesterday I kiln washed the shelves. As soon as I get the space rearranged so there are no flammables near the kiln, I'll do my test fire and then I'll be ready to get to work.

  7. Hi Linda. A buddy of mine melts glass into bowls all the time. Some does lose it's color at high temps.Best to have a consistent source so you can test and know what to expect.I have seen carpet tacks fired to cone 9 in porcelain.They bent but did not disappear, Good luck.

  8. Great job, Linda! Experimentation is key. Really like the brownish plate with the circles.

    Wanted to share that I was in our village yesterday and stopped in with a friend at a craft shop. She had the most incredible clay items, pottery, sorta - flowers - tiny little flowers painted so they looked like flowers in vases. These were priced at about $25.00. The orchids went as high as $600.00. She can't keep black orchids in stock.

    If you'd like info I'll be happy to stop by.

  9. Hi Michele, thanks, I had always wanted to try glass too and then I thought these flowers would be perfect since they wouldn't be functional and if the glass was crackled it wouldn't matter.

    Hi Mary, thanks, I love experimenting hopefully I'm not going off on too many tangents.

    Hi Cindy, thanks, that was the second test glass I did, now I'm on to many more. Ha.

    Hi Growin Granny, thanks, congrats on your kiln, the world of clay is wide open to you. Hope you post some of your results so I can see them. It doesn't take much glass to give an effect. Also I read to make sure the glass is in a more rounded object so it doesn't break the edges and flow on your kiln shelf. Can't want to hear about your experiments.

    Hi Dennis, thanks, yes I think a consistent souce of the beads and then also using them consistently too, on top of same glaze and same clay. So many tests to be made. Perhaps I'll try these tacks in my raku kiln, don't want to contaminate my big kiln with lead if there is any.

    Hi Kittie, thanks, I was just thinking of making ceramic flowers today and a few months ago I drew a vase in my journal with a perpetual flower; would love to learn about the info on those flowers you mention especially the black orchid, do stop by and find more out about them for me, thanks. This kiln load I have glazed many of the flowers I made different colors so we shall see how they turn out. Now to determind how to mount them to some type of metal rods. So much to do so little time.

  10. Oh Kittie, thanks, the plate is a little test plate about three inches square, I'll have to make a larger one, the circles that are darker are rough but the one is soft to the touch.

    Kittie, remember the famous murder, The Black Dahlia? wasn't it a book and a movie too. Something alluring about a black flower. I googled Black Orchid and there is one that grows in Belize. I'll have to make a black flower next time, so many possibilities was what I was thinking while I was glazing this load of flowers. Thanks again.

  11. So many experiments! I think you were a scientist in another life Linda! I enjoy following your tests. Have often thought fleetingly about playing with glass with my pieces. It's fun to see your process and results!

  12. Linda- you are up to some cool stuff over here! A friend of mine who is a glass blower turned clay junkie is experimenting w/ fusing glass & clay. Great experiments (I love experimenting!) & fun results!

  13. Hi Patricia, thanks, you know I may have been a scientist, it is so much fun trying something and seeing the results and logging them all down and then trying something else, I just have to be careful not to go off on too many tangents.

    Hi Becky, thanks, I hope you post some of your friends work and results, does your friend have a blog, it is so much fun learning about everyone else's experiments, process and progress.

  14. linda, what are you using for glass? a friend of mine was using blue glass from broken wine bottles with some nice results... i was thinking that is what i would try.

  15. Hi Michele, thanks, just some glass I had in my stash. There's a glass blowing shop near me I'm going to check with them and see what they recommend.


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