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Fused Glass – Experiment Continued

I am experimenting with float glass. Float glass or window glass is less expensive than the glass that I normally use for fusing.  That’s a good thing. But, working with float glass has some challenges. The dish above is the result after my first experiment. I created the pattern in the first firing which turned out well, but in the second firing, to give it shape, it got cloudy along the edges. I will have to do some more testing and experimenting.

Tech Stuff for Glass Geeks

I don’t have a tin scope to detect which side of the float glass has the tin on it.  If I find myself using a lot of float glass I will definitely have to get one.  While experimenting, I didn’t think it would matter much. This may have been a bad assumption.  When I first full fused the glass the back was cloudy the front was shiny. I sand blasted the back before I slumped it hoping to get a soft cloudy look on the back  after the slump. The back turned out exactly as I had hoped. Unfortunately, after the slump the top of the piece was cloudy particularly along the curved sides. After doing some research on this I believe what happened is not devitrification, but something called tin bloom. Tin bloom is apparently quite common when float glass is slumped or heated a second time. Back to the drawing board…

7 thoughts on “Fused Glass – Experiment Continued

  1. chaniarts says:

    it occurs when the tin side is up and is compressed during slumping. if you had used borax on the full fuse cycle, it wouldn’t have occurred.

    you can only put borax on the top and edges. if it gets on the bottom side (or between layers if you’re doing something multilayered), it will stick REALLY well to the kiln wash and pull chunks of it up. if you use a fiber shelf, it might even pull chunks of the shelf up (damhikt).

    i mix up a batch of borax, but use a paintbrush to slosh on a thick coat on the top and sides, let dry, then clean the bottom well with plain water.

    you have to go to at least 1430 for borax to shine up. however, it solves both devit and tin bloom on float.

    • Margot says:

      I have heard about and used the borax solution for devit, but not for the tin bloom. So does the borax dissolve the tin? I will have to give that a try.

      It took my sharp brain a moment to realize that “damhikt” stands for “don’t ask me how I know this.” Well I learn that way too!

  2. chaniarts says:

    borax doesn’t dissolve the tin. borax, at fusing temps, melts and coats the float such that the tin doesn’t have any exposure to air. it actually is a ‘glass-like’ type of material that is clear, so can hide a multitude of float sins. it is softer than the float and does dissolve over time (acid rain outdoors, alkaline dish detergents, etc), but since the glass underneath remains shiny, that’s not detectable.

    • Margot says:

      This brings me to the question, how do you make your borax solution and keep it from running off the glass. If it coats the glass covering the tin it sounds like it would need a pretty substantial coating.

      • chaniarts says:

        i add a couple of tablespoons of borax powder into an empty jar with a squirt of dish soap. fill with hot water and shake. add borax until no more dissolves. decant into an empty (cleaned well) windex bottle.

        i then can spray it on something, or use a large artist paintbrush to spread it on the glass. let dry, then clean off any that seeped onto the bottom.

        the soap acts as a surfactant, so it spreads easily. you just need a full thick coating of the liquid; you’re actually not putting the powder on the glass. you don’t want to use so much it spreads off the glass. when the water evaporates, you’ll see a thin white hard film; that is the borax.

        if you miss any spots, you’ll most likely get devit there, or it have a subtly different surface look which will be noticeable.

  3. Pomme says:

    I bought a really cheap UV light-m the kind they use in clubs and bars to see if you money is counter-fit or not and it makes finding the tin side of glass so much easier! Look for instructions online- lost the link- sorry! Just be careful- do not look directly into the UV light as it will damage your eyes!

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