How Glass Fibers Are Spun for Insulation

A 1933 invention by Games Slayter that describes the process of melting glass and blasting it into fine, flexible fibers to create insulation.

What it covers

The patent details a method for producing glass wool by melting glass and using high-velocity steam or air jets to attenuate the molten material into thin, flexible fibers. These fibers are then collected to form a mat or batt of insulating material. By controlling the temperature of the glass and the pressure of the gas blast, the process creates a lightweight, fire-resistant, and thermally efficient material that traps air within the fiber matrix.

What it doesn't cover

• —Does not cover the chemical composition of the glass itself.
• —Does not cover the use of centrifugal force or spinning disks to form fibers.
• —Does not cover the application of binding resins to hold the fibers together.

The clever bit

The invention recognized that high-velocity gas jets could stretch molten glass into fibers thin enough to be flexible, rather than brittle, by rapidly cooling them during the attenuation process.

Why it matters

This technology enabled the mass production of fiberglass insulation, which transformed the construction industry by providing a cheap, durable, and fire-safe way to insulate homes. It turned a laboratory curiosity into a standard building material used in almost every modern structure.

Real-world examples

• 1.Residential attic insulation batts
• 2.Commercial building HVAC duct lining
• 3.Industrial pipe insulation