The process for manufacturing fiberglass has changed a bit since the innovations of Kleist and Slayter. Their method of subjecting a stream of molten glass to pressurized air or steam is still in use, though in an updated form. The more common method of production involves forcing molten glass through tiny nozzles to create fine strands of glass, which are then drawn into a spool.

Different kinds of glass fibers are produced, depending upon the application for the finished product. The kind of glass fibers used in insulation, for example, are created in such a way as to trap lots of pockets of air in the glass. This has obvious advantages for a product used to insulate. Some types of class are created to have a higher tensile strength, while others are formulated to be especially resistant to certain chemicals or environmental conditions.

The most common applications of fiberglass are in the building industry. Most new houses are insulated using fiberglass batting and standard asphalt shingles also contain fiberglass reinforcement.

In addition, fiberglass combined with resins is used in numerous applications where a strong, lightweight, and highly durable material is called for. This includes components in the auto and aviation industry, boat construction, sporting goods, storage tanks, shower stalls, and numerous other examples.