# 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.

- **Patent:** US 2133235
- **Original title:** Method and apparatus for making glass wool
- **Owner:** Owens Illinois Glass Co
- **Granted:** 1938
- **Status:** Public domain (expired)
- **Times cited:** 22
- **Field:** mechanical, materials

## What it does

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 does NOT 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.

## Real-world examples

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

## 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.

## Frequently asked questions

### What does How Glass Fibers Are Spun for Insulation cover?

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

### Who owns patent US 2133235?

Owens Illinois Glass Co owns this patent, granted in 1938.

### When does this patent expire?

This patent has expired and is now in the public domain — anyone can use the invention freely.

### What is patent US 2133235 cited by?

This patent has been cited by 22 later patents that build on its ideas.

### What problem does this patent solve?

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.

### What does this patent NOT cover?

Does not cover the chemical composition of the glass itself.

**Full plain-English explainer:** https://patentbrief.org/patent/us/2133235/fiberglass-glass-wool-slayter

**Original patent:** https://patents.google.com/patent/US2133235

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_Source: PatentBrief — https://patentbrief.org. Patent facts are from public records; the plain-English explanation is PatentBrief's._


## Related patents

Semantically similar inventions in the PatentBrief corpus:

- [How Corning Invented Modern Fiber Optic Cables](https://patentbrief.org/patent/us/3711262/optical-fiber-waveguide) — A 1970 method for creating glass fibers that carry light over long distances by layering glass inside a tube and drawing it into a thin, solid strand.
- [How the Float Glass Process Makes Perfectly Flat Window Panes](https://patentbrief.org/patent/us/2911759/float-glass-pilkington) — This 1954 patent describes the float glass process, a method for creating high-quality, perfectly flat glass by floating molten glass on a bath of liquid metal.
- [Making Strong, Porous PTFE: The Gore-Tex Process](https://patentbrief.org/patent/us/3953566/gore-tex-expanded-ptfe) — This patent describes a specific process for rapidly stretching a highly crystalline form of PTFE plastic to create a strong, porous material with a unique internal structure, forming the basis for products like Gore-Tex.
- [How Willis Carrier Invented the Modern Air Conditioner](https://patentbrief.org/patent/us/808897/air-conditioning-carrier) — Willis Carrier's 1906 patent for an apparatus to control humidity and temperature, forming the technical foundation for modern air conditioning systems.
- [How the First Cotton Swabs Were Mass-Produced](https://patentbrief.org/patent/us/1721815/q-tip-cotton-swab) — Leo Gerstenzang's 1929 patent for the automated manufacturing of cotton-tipped applicators, the invention that created the modern Q-Tip.