Inclusions are any item that can be fused between layers of glass, of course with the exception of glass itself.

These foreign substances add character, color and texture.

These objects have unidentified expansion features that are not at all like the glass that it is being fused into.

Because of this, the objects need to be thin and light enough for the glass to expand and contract normally.

If the enclosure is too thick for the glass, the glass will crack.

This is especially true with things like heavy coins or bulky washers.

There should be enough glass around the area for the insertion to be sealed inside the glass.

Best results are obtained when the object is completely sandwiched between layers of glass.

So, what is the most frequently fused addition?

Copper is the number one item that is used for glass fusing.

inclusions, enclosure, insertion


Air bubbles – Bubbles don’t have to be avoided in your fused glass experience. They can be deliberately trapped between layers of glass to add texture and dimension to your artwork. There are several techniques to achieve this aspect.

Fiberglass strands – Be sure to insert some glass spaces when firing fiberglass. The resin binder needs to be burned off, and scraps of glass between your layers will allow this to occur. The resin should burn off before the top layer has a chance to slump into the bottom layer.

Metals – Gold is said to be the first metal that was used as an enclosure in glass. Some of the expensive metals are: silver, platinum and palladium. These metals tend to maintain their color even in the heat of the firing process. Some of the least expensive metals are: Aluminum and copper . These metals change color. Aluminum tends to turn black when fired. Copper on the other hand turns an unpredictable color ranging from a reddish-orange to a bluish-green.

Mica or mother of pearl – Use these natural substances sparingly. They can be used in powder or chip form.

Miscellaneous items – Some of the numerous miscellaneous items that can be fused between layers of glass would be: leaves, twigs, and cellophane wrappers, washers, razor blades and coins, etc. Some of these will frequently carbonize from the firing procedure and even result in an almost ghost image sealed in the glass.

There are some objects that can’t be used as an insertion.

These would include items like: paper, plastic, hair, fabric, string, wood or any food items.

Some plants can be used as an enclosure because they will leave a skeleton in the shape of the inclusion.

These plants would be ivy leaves, ferns and heather.

Try some of the objects in your glass fusing experiments.

They can really add some interesting and different effects.

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