Fused Bottle Glass Donuts – Part 2

Fusing bottle glass donuts can seem like a very easy process, until you run into a problem and can’t figure out where things went wrong.  For example, if your donuts have a ring of devit on the inner edge, how did that get there?  and how to fix it?  I ran a little test to see how the glass moves when donuts are fused.  This is an easy test, and one I would suggest for everyone to try as all kilns fire differently and this will give you valuable information about your kilns firing process.

Begin with clear glass donuts, try to use ones that are the roughly the same height and width.

Clear bottle glass donuts

Using fusible glass paint, I’ve painted the inside of one donut, the outside of the next, the top cut edge of the third, and the bottom cut edge of the fourth:

Paint the different sides of the donuts

Now fire to a full fuse using your fusing schedule, or mine.

donuts after firing

You can see the inside of the donut has ended up mainly on the bottom of the fused donut.  The outside surface stays mostly on the outside of the fused donut.  The top cut edge gets smaller as it slides into the center of the donut, and the bottom edge stays pretty much where it started.

I suggest keeping these fused donuts handy to compare fusing issues to and help trouble shoot.  You can also use this information to embellish your fused glass donuts.  I tried some other combinations that you may find interesting:

Mica – when painting mica onto fused items, it’s works best on an etched or slightly rough surface.  I tried using the rough sawed edge just to see how well the mica fused:

Fused cobalt donut with mica
Cobalt donut with mica

The mica adhered well during the firing, and made an interesting ring around the top of the donut.  The mica was trapped in the saw marks and is more visible there.

I also tried the same experiment with clear donuts, painting two clear donuts with gold and copper mica on the cut edges, and firing one gold side up and one gold side down.


The mica sticks better on the top edge, washing out somewhat on the bottom surface.

Ideally, mica works best on already fired donuts that are etched or tumbled, then painted with mica and fired to a slump temperature.

I also tried glass paint in different colors on the inside and outside of my donut:

I think this is an intriguing result that needs more practice and some tweaking.  If you’re not sure where to start with making your own fused glass donuts, check out these tutorials for help:

Fused Glass Donuts and Rings

Cutting Bottles with a tile saw

If you’d like to skip the cutting and get straight to the fusing, check out our ready to fuse donuts or fused and ready to use donuts


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