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An "inclusion" is a material that is trapped within the layers of glass when it fuses. Inclusions can give a piece texture, character, and color that glass alone can't achieve.

The key criterion when using inclusions is that the foreign material, which may have different expansion characteristics than the glass, is thin and weak enough to allow the glass to expand and contract normally. If it is too thick or strong, or has a dramatically different COE, it will cause the glass to crack as it cools.

Aside from air bubbles, which are present in most fused pieces, the most frequently used inclusion is probably copper.  Other common inclusions include gold and silver foil, but organic materials (such as leaves and various fruits and vegetables) can also be used.  Experimentation often pays off with unexpected results -- just be sure to use items that are small or thin enough that they can be contained within the glass without cracking. 

For a list of inclusions by category, click here.


Copyright 2005 Brad Walker.  All rights reserved.

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Copyright 2005-2006 by M. Bradley Walker.  All rights reserved.

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