Types of Lampworking Glass Rods:
Soda Lime (Soft) Glass:
Bullseye: This is an American glass company that is well known in the fusing world. It is a soda-lime glass and the rods are 4 to 5 mm in diameter. The coefficient of expansion is 90. The annealing temperature is 940°F and the strain point is 820°F. The rods come in opaque, opalescen,t and transparent as well as frit and stringers. This glass has a slightly stiffer working condition than Effetre.
Effetre aka Moretti: This glass was known as Moretti for many years and when the ownership changed, so did the name. It’s now called Effetre. Most beadmakers use both names. The company is located in Italy. It is a soda-lime glass and the rods are 5 to 6 mm in diameter. The COE is 104; the strain point is 840°F and the working temperature is 1700°F. The annealing range is between 920 and 968 degrees. The glass comes in transparent, pastel, special, alabaster and opalino. The alabaster & opalino rods have a slightly higher COE (melt at a lower temperature) so are not always completely compatible with the regular colors.
Lauscha glass: This glass is imported from Lauscha, Germany. Most of the colors are compatible with Effetre, but some are not. The COE is 95 – 105.
Satake Glass: This glass is manufactured in Japan and is extremely soft. It needs to be worked in a softer, cooler flame. The coefficient of expansion for the soda lime colors is 113 and that of the lead colors is 120. The annealing temperature is 890°F.
Vetrofond (Murano) glass: Originally started by a family from the Moretti family, this glass is made from an almost identical formula to Effetre. Its COE is 104, like Effetre, so its compatible. The company is no longer producing glass, but you can still buy rods from a variety of vendors.
Borosilicate (Hard) Glass:
Glass Alchemy: This company produces borosilicate that is compatible with Pyrex clear and Northstar similar to Northstar glass. The COE is 33. The strain point is around 950°F and the annealing point is between 1000 and 1112°F. They product both transparent and opaque rods and frit.
Momka: Boro glass started by Momka Peeva, a Bulgarian woman. It has the same COE, annealing, and strain points as the other boro glasses.
Northstar Color Rods: This is a company that produces what is known as hard or borosilicate glass that is compatible with Pyrex clear glass. The coefficient of expansion is 33. The strain point is around 950°F and the annealing point is between 1000 and 1112°F. It comes in both transparent and opaque colors.
Pyrex: The term “Pyrex” is a brand name, originally trademarked by Corning, but now manufactured by Schott. Pyrex refers to any clear borosilicate glass.