Tuesday, July 29, 2008
Wikibeadia: Kiln Annealed?
(Flameworked glass beads by Cindy Gimbrone)
(Fused glass gem by Lynn Davis)
When buying glass beads and/or fused glass one important feature handmade glass art beads typically have that craft store beads don't have is artists will kiln anneal their glass beads.
Why should you care about kiln annealing? Kiln annealing strengthens glass by allowing the glass to cool very, very, very slowly. If properly done, it relieves any stress in the glass and the beads won't crack.
Below is a picture of a set of glass beads I purchased at a local craft store:
As a glass beadmaker, I know by where the crack is, that the bead has not been kiln annealed. A crack along the bead hole means the glass cooled too quickly. Glass cools too quickly when it hasn't been placed in a heated kiln.
Here's a picture of me placing a hot glass bead into my heated kiln to anneal. Notice the temperature on the kiln reads 968 Fahrenheit, the proper temperature to anneal soda lime glass. (Ignore the hat and sweatshirt, it was the winter and my studio is unheated.) My kiln has an automatic cut off switch so when I open it, the electricity to the kiln shuts off. An important safety feature as are my safety glasses, my kevlar gloves and leather apron.
Did you know a properly annealed glass bead will bounce rather than break when dropped on the floor? Although I don't recommend you start dribbling your glass beads, I have dropped them on my concrete floor by accident and they do bounce.
So when buying art glass beads, check to for the words "kiln annealed" to ensure your treasure will last a lifetime.
Written by Cindy Gimbrone, glass beadmaker, who's accidentally bounced many beads off her studio floor.