Boro Glass Beads
Lampwork glass beads at Alaska Boro are each individually made by hand. Each bead is crafted using a lampwork torch heating glass in excess of 1500 degrees Fahrenheit. All lampwork beads are made using colored boro (borosilicate) glass from Northstar Glassworks and clear boro from Simax. For clear Simax boro, the melting point is 1517 degrees Fahrenheit with the working temperature at 2300 degrees F.
Borosilicate (boro) glass is best known for its very low coefficients of thermal expansion. i.e. Pyrex cooking ware. Boro is also known as hard glass which has a coefficient of expansion (COE) of 33. Soft glass, also used for making beads, has a COE of 104 to 90 depending on manufacture. Glass objects made with different glass COE’s will result in a product that is subject to cracking due to uneven thermal expansion even after annealing.
Beads made at Alaska Boro have bead holes of five different sizes. Holes are either 1/16 inch (1.58 mm), 3/32 inch (2.38 mm), 1/8 inch (3.18 mm), 3/16 inch (4.76 mm) and 1/4 inch (6.35 mm). Hole sizes are always slightly larger than the stated size due to the thickness of the mandrel (bead) release. A rough guideline is to add .006 to the diameter to achieve a closer true hole size.
Often handmade boro beads are lined with sterling sliver to have the general look of the popular Pandora style. For these ‘special’ beads, a 3/16 inch mandrel is used along with mandrel release to achieve the desired hole size.
Boro beads at Alaska Boro are kiln annealed at 1050 degrees. Beads are slowly cooled through the boro glass strain point at 950 degrees Fahrenheit using a digital PID controller to remove any stress. In addition, each bead hole is hand cleaned of release prior to or after the annealing process.
Bead colors are dependent on viewing conditions and monitor settings. Beads will look livelier outside and somewhat muted inside. Images are as true to life in color as possible. i.e. beads that look dark on the site will look dark when received.
The size of a bead image can not be used to determine actual size. Images are larger than life to enhance the view of boro colors and designs. Please use the size data as stated in the product description to determine actual bead size. Sizes are stated in millimeters with the first dimension being the bead diameter, followed by thickness and then the approximate hole size.
Boro beads have a unique look when compared to soft glass beads. Namely, that striking colors produce various color shads while using the same colored rod of glass. Colors ranging from green to blue greens, to blues and browns can be achieved from one rod by varying flame chemistry.