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Stained Glass Minute (Volume II)

Coefficient of Expansion (kō-ə-‘fi-shənt ‘əv ik-‘span(t)-shən)

Noun (Physics)

The fractional change in length, area, or volume per unit change in temperature of a solid, liquid, or gas at a given constant pressure.

So, what does this have to do with glass? Everything.

Three pieces of glass fused using glass with different coefficients of expansion (COEs)
Examples of the coefficient of expansion (COE) differences at work in glass pieces

When working in hot molten glass and attempting to combine two glasses into one, they must share the same coefficient of expansion (COE) properties. We call this their COE number. For example, if you attempt to fuse a COE 90 piece of glass to a COE 96 piece of glass, they do not melt at the same rate, affecting the way your piece looks when it cools. Sometimes, (cough), some people use this paradox to make awesome stuff.

Like taking a diamond of COE 96 Spectrum Southwestern reactive fusible and cap it with COE 90 Bullseye Clear Tekta, when it fuses, the Tekta pools in the center and draws up the sides of the Southwestern, thus making it look as if there's a pool of water or even a bubble on top of the Southwestern, but... it's GLASS!

A pile of glass pendants all different colors and designs
Arrow points to a pendant made with two different COE glass pieces

Want to own a piece of this cool paradox? Our Artist Guest of Honor Leia Powell brings her fused glass jewelry to our Dealer’s Room and Art Show every year!!!

Stay Glassy,

Leia Powell

Master Stained Glass Artisan

Wildcat Mountain Artistry

1 Comment

Aug 15, 2023

Yeah! Science! ~Leia

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