Collecting Antique Glass Insulators
If you've ever walked into an antiques shop and seen funny bulbous-shaped colored glass objects on a table and wondered, "What the heck is that?" the answer is simple; you are looking at glass insulators. What are glass insulators? They were used along old telegraph lines to keep live electrical wires away from the wooden telephone poles. They hearken back to the days of old railway travel, of telegraph lines and the advent of the mass communications age. Today, porcelain and ceramic insulators are favored for modern use, but the beautiful and functional glass insulators live on in the nascent hobby of collecting antique glass insulators.
The History of Glass Insulators
As railway lines and telegraph lines spread throughout the United States, electricity needed to be carried along powerful cables along those same lines. But live electrical wires and wooden telegraph can't touch - they can start a fire. Electricity conducts through certain materials, but other materials resist conduction. Glass and porcelain are two such materials. Glass insulators were manufactured so that live electrical wires could be strung from pole to pole without the wires touching the wood and starting a fire.
Insulators are made from glass, porcelain, rubber, and sometimes other materials, but the ones you see most frequently at antique stores, flea markets and yard sales are made from glass. The unpainted ones in the images accompanying this article are all glass insulators in my own little collection. I found mine dumped on the edge of the woods near our farm. At the time I found the box of glass insulators, the old Norfolk-Southern railway line nearby was decommissioned and the state was transforming it from an abandoned railway line into a multi-purpose recreational trail. While you can still see some of the listing and leaning old telegraph poles along that same trail with the green, blue and white insulators winking along the cross arms, most of the insulators have either fallen off or been removed over time. I suspect that my group of insulators may have been collected from along that railway bed.
Major Types of Glass Insulators
Glass insulators come in a fascinating array of colors, sizes and shapes. The major producers of glass insulators during their heyday included:
- Hemingray - Hemingray produced glass insulators from 1848 - 1972. Their website offers a guidelines for identifying your Hemingray insulator and the approximate time period of production. Hemingray stamped the glass with the company name and many Hemingray insulators also have an identification number, indicating the type, stamped near the name.
- Whitall Tatum
- Many others
Glass Insulator Shapes
Insulators come in a wide variety of shapes and sizes. Most have a depression or indentation in the center. This is how the insulator fitted onto the crosspiece of the wooden poles lining the railway line. They were threaded onto pegs and glued into place. Insulators typically have a space for the wire or a threader near the top. The electrical wire was threaded and looped around this section.
Some insulators have glass 'teeth' along the bottom ridge, perhaps to help them grip the wood better once placed into position. Others have a smooth edge.
Colors of Glass Insulators
Glass insulators come in a wide range of colors. You will find:
- Light aqua
- Cobalt Blue
- Ruby red or Amber
- Peacock of "Hemingray" blue (named for the manufacturer)
Why were different colors made? Railway lines often shared the right of way with several companies. According to Insulators Info, a 1909 catalog listed various colors of glass insulators to help the linesman distinguish which insulator and line belonged to which company. Company A may choose clear, while Company B used only Hemingray Blue, etc. The colors varied even among similar colored insulators listed for sale in manufacturer's catalogs, and a wide variation may be found among similarly colored insulators from the same company.
Identification and Value of Glass Insulators
Most collectors agree that the best way to identify and determine the value of a glass insulator is to begin with whatever markings are on the piece itself, and to use a good price guide and identification book. Although the hobby of collecting glass insulators is fairly new, there are many good books out on the market that can help you identify and price your glass insulator.
As with most glass antiques, condition and rarity are most important to determining value. Cracks, chips or damage of any kind on a glass insulator decrease its value significantly. In most cases, rarity, rather than age, also impact value. The insulators I found along the edge of the wood had cracks and chips and when I looked them up, were all very common insulators, making them worth very little. When in doubt, check the price guides.
Collecting and Displaying Glass Insulators
The hobby of collecting glass insulators is a fairly new hobby, but there are collectors worldwide. There's even a club, the National Insulator Association, to encourage collecting. There are events, meetings and more.
You can find glass insulators for sale on eBay, at flea markets, yard sales, auctions and antique shops nationwide.
Glass insulators in perfect condition are best left as they are. They can be displayed on a shelf or on a windowsill. Mine make beautiful 'stained glass' effects from their place of honor on the windowsill. Some people paint the very common or damaged ones to make them into pretty paperweights, like the sunflower one shown here that I bought on eBay. Before transforming your glass insulator into a craft project, be sure you are certain of its value and are willing to part with it, because once transformed it loses any inherent value it had as an insulator.
Collecting glass insulators is a fascinating hobby. It's a glimpse back into time, when coal-fired engines chugged along railway tracks and telegraphs clicked out messages to waiting towns.
- Glass Insulators Collectors Reference Site
- Hemingray.info - Home of the Hemingray Glass Insulator Database
Hemingray.info is Christian Willis' Hemingray glass insulator web site.
© 2012 Jeanne Grunert
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