Coefficient of Expansion (kō-ə-‘fi-shənt ‘əv ik-‘span(t)-shən)
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.
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!
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!!!
Master Stained Glass Artisan
Wildcat Mountain Artistry