E-glass (“Electrical” grade glass) is by far the most used fiber in reinforced plastic composites. In many industries, it represents over 90% of the reinforcements used. Its main advantages are:

• Low cost

• High strength

• Light weight (relative to steel)

• High chemical resistance

The main disadvantages are:

• Low modulus (relative to other reinforcing fibers)

• Low fatigue resistance (relative to carbon fibers)

• High weight (relative to other reinforcing fibers)

• Highly abrasive when machined

• Susceptibility to stress corrosion

Because of its widespread use, the advantages have a tendency to outweigh the disadvantages.  Almost all glass fibers are sold in strands of grouped fibers, or rovings, associated with a particular yield.  The yield is the number of yards of roving per pound. The metric unit of measure is TEX which is the weight in grams per kilometer (1,000 meters).