Antique glass insulators



2015-06-26 11:16:24

Antique glass insulators were an early means of insulating communication wires. They are often discovered alongside (disused) railway tracks. Although the practice of collecting antique glass insulators only dates back approximately fifty years, it is a very popular pastime, particularly in the United States.


Antique glass insulators were designed in the early 1800s as a means of insulating early communication wires. Their production spans more than 100 years - a period punctuated by changed in design and use.

In 1844, Morse's first telegraph line was installed between Baltimore and Washington. To produce the current needed, wet cell DC batteries were used. These early batteries comprised glass tanks full of electrolytic solution containing copper, carbon, or zinc electrodes. The batteries were often insulated from their supports with "battery rest insulators" - also known as antique glass insulators.

During the early years of telegraph development, while it wasn't known what worked best and for which reason, antique glass insulators underwent many design alterations. "Ramshorn" designs, which were made throughout the 1870s, were the most popular.

Eventually a design was developed that proved to be far superior to every marketable alternative: an inverted cup shape complete with a groove, wooden "pin" and "pin-type" inslulator. The insulator was glued to the pin with molten sulphur, tar, burlap, etc, and the pin set into a hole in a crossarm. Since the pin-hole was plain and smooth, these antique glass insulators are known as "threadless".

Collector's Guide

Fake and Altered Hemingrays

  • Crackle glass Hemingrays

The surface of a crackle glass Hemingray will have a crackled appearence. The effect is caused by intentionally heating up and then rapidly colling the glass in order to create internal fractures. Genuine, clear crackle glass Hemingrays are very often painted or sprayed more vibrant colours. Clear Hemingray insulators are the most frequent victims of this practice because they were made in such abundance. Spraying and painting clear crackle glass insulators completely strips them of their worth.

  • Painted or stained Hemingrays

If a coloured insulator has a mould and date code it was produced after 1933 and therefore after Hemingray stopped making brightly colored glass (with the exception of amber and carnival) it is a fake.

  • Etched or sandblasted Hemingrays

Sandblasted/etched logos are not original to the insulator. Items which have been altered in this way are worth very little and are of no interest to serious collectors.

  • Irradiated ("Nuked") Hemingrays

Some insulators are exposed to radiation to alter their colour. These insulators are not considerd original and are therefore worth very little, although there are often quite pretty.

  • Mechanically altered Hemingrays

Sometimes, people will cut insulators apart, or put mismatching pieces together to create a fantasy insulator.

  • Fake Carnival glass Hemingrays
  • Hemingray "Insulcats"
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