Use Your Glass Grinder Waste!

For many years I have been accumulating dried glass grinder waste in huge pickle jars with no clear idea about what to do with it. But now I have.

But what do you do with the sloppy mess in your glass grinder when you’re cleaning it out? Have you also been saving it in the hope that one day you’ll figure out what to do with it?

Today I would like to share with you the results of early experiments firing glass grinder waste in a kiln. I hope it encourages you to creatively use what would otherwise end up blocking your drains, mixed into your compost heap or in landfill.

Using Glass Grinder WasteOn the right you will see a picture. At the bottom left is a plastic spoon containing some dried glass grinder waste. You will also see a picture of a biscuit cutter. From this it is easy to guess that you put spoonfuls of glass grinder waste inside the biscuit cutter (and tamp it down as best you can).

The picture also shows the results of firing some of this waste with a full fuse schedule (the same as I would use for a coaster). And I can see no reason why it will not work similarly on a smaller scale in a microwave kiln to make faux rock pebbles.

The first thing you may notice from the picture is how much the finished hearts have shrunk compared to their original biscuit cutter outline.

Something else you can see is that some of the hearts are dark brown and glossy whereas others are somewhat paler and matt. The darker shiny side of these hearts was uppermost in the kiln. The paler matt side was against the kiln base. Incidentally, I was using Bullseye Thinfire paper.

If you look really closely you might see that the uppermost side of the hearts is uneven and lumps can sometimes be seen. Although there were no large pieces of glass waste, the dried glass waste had become lumpy over a period of time. I should have carefully crushed those lumps and sifted the powder, much like my mother used to do with flour before baking a cake.

You can also see a few “attachments” at the edges of the heart at the middle top of the picture. This is where the powdered waste has slipped and formed little blobs. Most of these blobs are easy to snap off but a few moments with a glass grinder with make the hearts smooth and shapely. It does however hint at the possibility of trying again either with the freeze-fuse technique, or mixing the waste with CMC in the way I describe here.

I particularly like the pale matt sides of the hearts because they have the visual appearance of a fine-grained sandstone.  There’s a sort of mother-Earth natural look and feel to the matt side. It is very different to what you might expect from glass. It makes me wonder if they would look good chopped up into little tiles and used as decorative highlights in a mosaic.

The dark brown shiny sides of the hearts I’m not so keen on. The colour and lumpy surface texture remind me of a rather unsavoury bodily product. It almost makes we want to make “novelty poo biscuits” as tasteless gifts. Urgh. Perhaps not!

Since taking the hearts out of the kiln I’ve chopped one up and returned a heap of the pieces back into the kiln on a full fuse schedule. What surprises me is that a full fuse schedule did little more than fuse the pieces together in the manner of a strongly tacked fuse with only a hint of sagging. This should not happen with a full fuse schedule.

I have also found that the glass of the hearts are a little easier to drill than “ordinary” glass.

Combining these two observations gave me a suspicion that the internal structure of the hearts is a myriad of tiny particles that have “reluctantly” fused together rather than fuse together into the solid amorphous mass we would normally expect when we work with fused glass. This led me to investigate a little more closely with thoughts of widely varying kinds of incompatible glass particles trying but failing to properly fuse together.

The obvious test for stresses cause by incompatible glass pieces is to see how strong the finished hearts are. I gave them a good bashing and none have broken. This gives me an impression that the structure of the hearts is strong, but more like the particulate structure of a piece of sedimentary rock than a piece of glass, where lots of tiny “incompatible” particles are only able to exert tiny stresses. So it does seem to me that I have made some artificial rock – a kind of slightly igneous but mainly sedimentary rock! How weird is that?

And finally, I should perhaps encourage you to make use of your glass grinder waste for health and environmental reasons. Powdered glass is a nasty product that can cause silicosis. It is also wasteful in environmental terms to dispose of something that can be used. It’s as simple as that!

So, that’s your lot for this posting. Have a go. Find a use for your glass grinder waste. Delight in your efforts to save the planet!


About chatterglass

Maker of stained glass frippery.
This entry was posted in CMC, Drilling holes, Experiment, Frit, Melting Glass, Microwave kiln, Money-saving ideas, Recycling, Tylo and tagged , , , , , , , , , , . Bookmark the permalink.

8 Responses to Use Your Glass Grinder Waste!

  1. Hi, me again. It’s after midnight, so I may have missed it but did you say that this is waste from various types of glass? So they are not all compatible? I too have been saving the waste from my grinder, and I have old stained glass, new stained glass, fusible glass, China crappy glass all mixed together. At one point I did fuse some but it turned this horrid grayish khaki color so I didn’t continue with it. I don’t think I threw it out though, of course not lol. I did think that because the initial glass pieces were so tiny that perhaps the COE might not be as important. Have you done any more experimenting with this?

    • chatterglass says:

      Yes Liz, the glass grinder waste I use is a random mix of whatever I have been grinding and mine will be a similar mix to yours. And yes, you are correct to say that the particles of waste will not be “compatible” and that COE is still important. However, we’re in luck because tiny little pieces of glass can only expand and shrink by a very tiny amount so can not build up large amounts of stress which means no cracking or shattering. I suspect it also explains why the nature of fused glass grindings seems to resemble particulate sandstone rock rather than a single amorphous glass lump – try drilling into fused glass grindings to explore this!

      The same explanation can be used to explain why some people get away with sprinkling a few coloured frits onto slumped bottles to make them more exciting. It also explains why small pieces of jewellery “cooked” in a microwave kiln do not habitually shatter or crack despite them not being properly annealed. So, size matters!

      As to the colour of fused glass grindings, it will depend on the mixture of colours in the grindings and, as you may know from painting, adding lots of different colours always seems to tend towards a murky brown sort of colour. I always seem to end up with fused glass grindings that resemble dog poo so you’re lucky to get khaki!

      Incidentally, even when fusing scraps of the same colour, you’ll sometimes experience colour changes. For example orange and yellow “ordinary glass” tends to go opaque and head towards red. A potter tells me “Oh, that’s probably just the cadmium burning off.”

  2. I like this, I too save little bits of glass, did you first put a magnet to the glass?

    • chatterglass says:

      Hello Phyllis. Thank you for the question. It’s always good to know I’m not talking to myself in a wilderness!

      I don’t use a magnet on the grinder waste on an assumption that it ought not to gather any magnetic material. Out of curiosity I’ve just had a sweep over some grinder waste with a nice strong neodymium magnet and it didn’t seem to catch anything.

  3. Wish i had saved mine now! What about those rocks or pebbles? How would you make them? I guess just shape them with your hands?

    • chatterglass says:

      Hello Valerie. I’m sure you’ll soon have more waste with which to do some experimenting. No, I never shaped them with my hands – circular blobs of scrap glass are produced by firing long enough for surface tension to pull in sticky-out edges. Try experimenting with freeze-fuse in chocolate moulds, perhaps using CMC gel as the carrier for glass powders, or just shovel into biscuit cutters. It’s all about experimenting to discover new things.

  4. enjoying reading your posts

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