Green Fused Glass Cabochons

Making Green Puddle Cabochons – Part 2 – The Cabochons

In Part 1 I covered making the puddle by fusing several sheets of Bullseye COE 90 glass, but didn’t get into how that became finished cabochons.

In this part I will cover making the cabochons from the puddle, from breaking up the puddle, grinding and preparation, full fusing and a final fire polish.

Breaking up a puddle is always something that makes me a little nervous. I suppose it relates to the act of breaking glass, and not being able to control the break. Yes, I know that is the whole point, and what gives that random effect, but still.

The way I break the puddle is to lay it over a piece of timber so it isn’t flat on the table, cover it with a good thick rag and whack it with a hammer. This is done on several sheets of paper so I can easily fold them up, along with all the slivers, and discard in the rubbish.

I continued this until I had a bunch of smaller pieces. If the pieces were too large for single cabs I either continued to break them up or took them to my diamond saw and cut them into smaller pieces.

Once this was complete I took them to the grinder and ground one edge flat enough so the piece stood vertically and didn’t lean, at least not too much. The reason for this is that if it leans too much it will fuse down and you will have one dominate colour on top, the colour of the top of the lean, and little banding.

Any fine edges or any real pointy bits were also ground off. Just so the fuse resulted in a more uniform shape.

Broken Fused Glass Puddle
Broken Fused Glass Puddle

All the pieces were then cleaned and placed on edge on Bullseye kiln paper for a fuss fuse. The firing schedule is below.

The result was good, but I did have a little devitrification on some pieces and a couple of rough edges.

Green Fused Glass Cabochons
Green Fused Glass Cabochons

The pieces that had bad devitrification were ground to remove most of it, but I didn’t worry too much as I intended to throw everything into the tumbler. I have found that 6-7 hours in a tumbler is enough to clean up any devit and remove rough edges.

In my tumbler I simply fill the barrel with a mix of small and larger pieces, along with a couple of tablespoons of 80 grit silicone carbide, then water to just below the top of the load.

6 hours later the cabs were removed from the tumbler, cleaned well to make sure no grit remained, dried and placed on a prepared kiln shelf.

Fire Polished Cabochons
Fire Polished Cabochons

These were then fire polished to a beautiful shiny finish, as you can see.

All done.

Firing Schedule

Full Fuse – Bullseye COE 90 Puddle Pieces to Cabochons

Please be aware that all kilns fire differently and this schedule may not produce the same results in your kiln.

Segment Rate (C/hr) Target (C) Hold (mns)
1. Strain Release 222 537 5
2. Process 333 780 30
Crash Cool Open Door 550 0
3. Anneal Full 516 30
4. Cool 83 371 5

Fire Polish – Same cabs as above after tumbling

Please be aware that all kilns fire differently and this schedule may not produce the same results in your kiln.

Segment Rate (C/hr) Target (C) Hold (mns)
1. Strain Release 222 537 5
2. Process 333 732 5
Crash Cool Open Door 550 0
3. Anneal Full 516 30
4. Cool 83 371 1

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