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For those of us who like to make an insulator hunt a real quest, this information is to let you know about the dangers of the lines. To show you a few of the basics in order to keep you safe. I have been a lineman since 1989 and may be able to offer a few pointers. Knowing a little about pole condition will get you a long way. The thing about old insulators is that they are always on old structures. Unless you support a rotten pole it will more than likely fall over. Just the fact that you untie a conductor may make the pole fall. There are many weights and forces to consider. There are various types of wires on poles. Telephone, telegraph, electrical lines are not obvious to a novice. Being able to identify what the wires are used for is skill the trained person has. I guess that I am trying to keep you insulator collectors out there safe. This information is for the people who want to be well informed. We all hope to have that ultimate insulator hunt.
For those of you who may not read this complete article, I'll repeat the Recommendations section here:
Recommendations
Stay off the poles! There are just to many factors for the average insulator
collector to keep in mind. Think about this and make your own conclusion. I conclude
that this profession is a dangerous one and the people doing the job must respect
this fact. Make good decisions in your life and “Be Safe”.
Happy insulator collecting!!
But, if you want more details, I encourage you to read on!
Safe Ways To Collect InsulatorsIt causes the insulator collector great happiness when a lineman has dropped a jewel for him/her to find. The feeling is excitement for the true collector. Line crews will leave the old hardware behind for many reasons. You will probably have the best chance to find insulators in remote area as most of a lineman’s climbing gear and tools must also be also carried in and out of these locations. Carrying out insulators and hardware is another trip and sometimes are left behind. The old hardware is generally thrown in the garbage so I guess collectors are doing an environmental service by picking up this unusable debris. I think it is a good idea to ask permission to hike into some areas. You never know when you may be on private property.
Bear and other wild animals are also a consideration. One area that I hunt is in Grizzly bear country. I always take a partner with me on these hunts and stick to the main right-of-way. Buy a map, know the area, look for bear sign (stools), carry bear spray, tell someone where you are, carry a first aid kit, take bug spray, take bee sting medicine, take a cell phone, are all good tips if you are a long way from civilization.
We all have our idea of the ultimate hunt. Try the railway line or the long lost mine. A nice long hike through the old right-of way is the way to find an insulator. This is the collector’s ultimate quest.
Most of these guys are not half bad. I have met macho linemen as well as gentle. If you luck out he may give you an insulator if you smile nice or give him a handshake. They have been known to drink a couple of soda pop after work as well. You get the idea. I am sure that every insulator collector knows at least one lineman. I know quite a few. I have heard stories of a fellow who offered the line crew $50 American for an insulator from the line they were working on. I later found out who this character was. He is one of the most active collectors and is a great guy.
Many insulator collectors buy their first insulator from the shelf of the old second hand store. Check that antique and junk store, you may find something great.
Insulators.info has an excellent insulator for sale page. This page has lists of insulators for sale at reasonable prices. I have had luck in trading insulators by contacting collectors listed on the web site. Insulators.info has a web ring where individual collectors have posted “for sale” lists and insulator information. Auction sites such as eBay have many insulators to offer in all shapes sizes and colors.
Crown Jewels of the Wire and other magazine subscriptions list “insulators for sale” at reasonable prices.
Important Safety Issues to ConsiderThe number one priority is your safety. Knowing what you are getting yourself can save your life. When you work for a utility all conductors on all lines must be totally isolated and grounded before any hand contact is made. You must contact the P.I.C. (Person In Control) in charge of the circuit for the appropriate protection paper work and/or switching. Any accidental contact is a major concern for the safety effort. Here are some ways that the conductor may become energized.
The motion of wind running across a conductor will cause a current to flow through the conductor. This current is enough to kill you so beware of a line you think may be de-energized.
If an energized power line is in the proximity of a de-energized conductor, its magnetic field will cause current to flow through the conductor. Remember the line may not be in view and could be crossing several spans or miles away. This current may be enough to kill you. You could even get a dangerous shock from a farmer’s fence that had been strung under a high voltage line.
All power sources must be considered. Back feed comes from many sources. Seemingly harmless conductor can be energized. “A piece of tech cable up a pole”, “an old signal supply strung on rail arms”, are examples of the endless possibilities. Do not assume the power was disconnected or conductor lying on the ground is de-energized. Back-feed will also occur when a customer hooks a generator up to his home panel. The power generated will back-feed onto the distribution system through the transformer. This could be deadly for a lineman.
The lightning can hit the line miles away and a surge of power will rush through the circuit. A lineman would protect himself with an equal-potential grounding system.
You could never know the status of a stretch of line unless you used an approved voltage tester (not a voltmeter) and some safety grounds are installed. This type of work is for the trained professional.
Pole SafetyBefore any pole is climbed an inspection of the pole must be checked. A pole will generally rot out at the butt, just under ground level. The problem is worse in damp, shaded or swampy areas. Insects can devour a portion of the pole butt as well. A quick test is to use a heavy hammer to drive your large screwdriver into the butt, just under ground level. Do this in a few spots around the pole. Is the base soft and mushy or solid and sound? Hit the base of the pole with a heavy hammer. The sound will give you a good idea if it is hollow. Another test is to give the pole a good push.
Remember that the butt is not the only place the pole can be deteriorated. Look for other signs of decay or abnormalities. A woodpecker can also do significant damage to a wooden structure. Do not take this lightly. You do not get a second chance.
The pole itself will give you some valuable information. On the face of the pole is a gain mark. Usually this will be a flat-planed area, which marks the pole 12 feet from the bottom or base of the hole. Often the date nail will be fastened on or near the gain mark. This mark allows a person to look at the height of the gain mark from the ground and determine how far it is planted into the ground. If the gain is 6 feet from the ground, it is 6 feet in the ground. Remember that the pole length could have been altered. I have seen pole butts cut off to fit a hole. This can be a dangerous thing to do as it deceives the person climbing the pole.
Ten percent plus two feet is an excellent rule of thumb. If the pole is 35 feet high you take ten percent of 35 and add 2. This means a 35-foot pole should be 5.5 feet in the ground to be at a safe depth to support itself. You always must take into consideration the soil type and water content of the soil. It’s hard to keep poles standing in a swamp or an unstable area. The height of a pole is usually stamped in the pole near the gain mark.
A nail with the date marked on the head. It is nailed into the pole near or on the gain stamp. This is an excellent warning device for the utility worker. If the pole is 30 years old or more it will tell me to pay extra care in assessing the stability.
Most utilities have a professional pole testing company do tests to determine the need to replace poles. The most common test is a butt test. A small amount of dirt is removed from the base of the pole and a plug of pole is drilled out from the middle of the butt. The condition of the wood removed is assessed and the pole is marked accordingly. If the pole is sound a test date and pole number is recorded and a tested date attached to the pole. If the pole is rotten it will be marked with an appropriate tag. “BAD ORDER POLE, DO NOT CLIMB” is what we use now. A red and blue tag system is also used. Red meaning bad order and blue meaning the pole could be stubbed. Some utilities use a “X” tag, meaning bad order pole.
If a lineman had to climb a pole he thought was rotten or in poor condition he/she would take precautions. One way to do this is to climb a safe distance (6-8 feet) up the pole and attach three or four ropes. The ropes can then be tied off in different directions so the pole will remain stable when he/she climbs higher. Remember that you must know proper knot tying methods and rope weight capabilities. For example power-braid nylon is stronger than regular nylon rope. The bigger of two identical types of rope, the stronger it is. You must know what you are doing!
I know a fellow who collects rail insulators. He has a love for trains and spends hours walking the tracks. I knew some of the places he had been going for years and was also aware that the structures were still standing but no conductor remained. I asked him one day how he was able to get the insulators down. He told me that a lot of the structures have guy wires and he climbed them to retrieve the insulators. This man is very lucky to have never fallen. These poles are many years old and some structures have fallen down. You must know that any pressure or weight put on a guy wire causes the pole to move toward the guy.
Hardware and anchor condition is an important issue. I have seen bolts so rusted that a bit of extra strain on a guy has broken the bolt or pulled a nut off. In days gone by, anchor rods were drilled through wooden pole pieces or deadheads and buried in the ground. As time passes the wooden deadhead will rot and the anchor pulls out of the ground. You must also consider that extra weight on a guy will cause a rotten pole to fall.
RecommendationsI would never let anyone take any unnecessary risks. If you don’t know what you are doing, stay down off the poles. If you insist on climbing to get insulators, be well informed and make good decisions. Line work can be dangerous for an experienced professional. Try signing onto a lineman’s chat line sometime. You might notice that most linemen would sign off saying, “Be safe” or “Work Safe”. There has to be a good reason they repeat this!
1. Preamble
1.1 Wood poles form an important part of the Power system inventory. They are used throughout the electrical system to support power lines at distribution and transmission voltages.
1.2 Wood poles must be handled with care at all stages of their use. They are a potential source of hazard to employees when they are being transported, stored, erected, climbed, sawn or made ready for disposal.
2. Testing Poles Before Working on Them
2.1 The requirement to make sure standing poles are safe before they are climbed is specified in O. H.& S. 19.3 and S.P.R. 404.1. (This is our local Safety practice regulation. May be different in other areas)
2.2 When assessing the soundness of a pole it is useful to know its identity, its age and the history of treatment. There are 4 other aspects of a standing pole which should be considered:
- condition of the pole - position and condition of the guys - The wind load on the pole and attachments, conductors, transformers, capacitors, reclosers, etc - condition of the earth
2.3 Visual Inspection: on the pole look for signs of decay, especially at the ground line, and breaks, splits and woodpecker holes. In the surrounding earth look for sloughing and swampy or water soaked soil. Check guys for slackness or excessive tension. A pole marked for stubbing or replacement must not be climbed unless it is supported.
2.4 Tests: If there is any indication of decay or damage resulting from the following tests, the pole or structure should be given additional support to ensure that it does not fall.
2.4.1 Sway Test: Severe internal decay and rot below the ground line can be detected by swaying the pole with hand lines or pike poles if attachments permit. Care is needed to protect employees and others against the possibility of the pole falling.
2.4.2 Sound Test: This is a means of detecting internal decay by discerning the sound when the pole is struck with a hammer. Hammer blows should be made around the pole from the ground line to about eight feet above. If the pole sounds hollow bore tests should be done.
2.4.3 Bore Test: The internal condition of the wood pole can be found by drilling it with a hand brace and an extended 13/16-inch drill bit. The penetration should be made at or below the ground line with the drill bit aimed at the centerline of the pole. The drill may be inclined 45 degrees to the axis to minimize excavation of the earth.
Indications of decayed wood are:
- increase in speed of penetration of the drill
- sudden collapse of wood under the drill
- powdery borings
If a hole gives suspicion of decay, 2 additional holes should be bored at the same level, displaced by 120 degrees for confirmation. Each bore hole should afterwards be plugged with a 7/8-inch diameter by 2-inch long treated wooden or 1 5/8-inch long plastic dowel.
If there is a confirmed internal decay, a pole inspector should evaluate its extent by calculating the effective shell thickness of the above ground and below ground portions of the pole. In an emergency situation crew should support the pole by following the procedures in section 3.
2.4.4 Prod Test: This requires a trench to be dug on the wettest side of the pole, 30 to 45cm deep and one shovel wide. Its length should be sufficient to allow a screwdriver to be used as a prod to find surface decay or cracks. The prod test may also be used above ground level where surface decay is suspected.
This is a West Kootenay Power standard and the rules and standards will change in each area. These are good guidelines to follow in the name of safety.
Ladders have been and will probably continue to be used to remove insulators from short rail and telegraph poles. This could be a very dangerous thing to do, not to mention illegal. I give you this information, as I know people won’t always listen to advice. At least you might look out for the hazards! I know that most insulator collectors stay with-in the law 99.9 percent of the time.
Something to remember when you climb a ladder that is leaning up against a rotten pole, the weight of you and the ladder may cause the rotten pole to fall.
Wood is an insulator but can become contaminated and wet. When a ladder is dirty and wet the insulation value can be decreased. Utilities have been going away from wood ladders. Some wood ladders have steel bracing built onto them. The steel in the ladder is a conductor and will complete the path to ground. Keep these ladders away from conductors.
Approved fiberglass ladders are insulated. This is the safest ladder for the utility worker. I could never recommend using a ladder for insulator collecting because there are so many other factors to be considered. Be safe!
Breaking glass, tie wire oxidation, wood dust, electrical arcing, conductor ends, are some of the things a lineman can get into his/her eyes. Just simply untying a copper conductor can make the oxidation on the tie-wire shoot into your eyes. Not a pleasant thing to happen. A utility worker should always have safety glasses available.
Hardhats are and have been standard issue for the utility worker. Chinstraps have recently been added to the list of standard safety items. If a worker is to be more than 10 feet off the ground he/she must be wearing a chinstrap to hold the hardhat in place. Remember, if you drop an insulator (by accident) from the top of a pole it can seriously hurt a person standing underneath. This sort of thing can and will continue to happen. Use common sense and it will never happen to you.
Harnesses are usually used for bucket applications although there are some harnesses you can climb in. Use the right equipment for the job and always inspect all harnesses for wear and defect. Do not use questionable equipment, as it is important to your well being. Remember that climbing is a skill that takes years to develop.
Pole belts come from a variety of manufacturers. It is important to be familiar with your equipment and to do routine inspections each time you use it. I have been climbing poles for several years and still do not feel totally comfortable in all situations. Leaning poles, climbing obstructions, touch potential, shell rot, pole stubs these are just some of the things you may run into. If your a person interested in doing line work for a living or even in hanging lighting in your own yard, do some practice first. Find a stable pole with no utilities attached and climb up six feet, move around the pole, climb down, lean out, get used of your equipment. Use common sense as you are taking your life into your own hands.
Most utilities have changed to a two-point attachment system. A lineman’s belt is equipped with a second belt or pole strap. Before the first pole strap is removed to belt around an obstacle, the second strap is attached. The worker is never disconnected from the pole.
Unqualified workers should not climb utility poles. There are just to many risks involved in doing this. The point to giving the insulator collector this information is to educate them to the hazards of climbing poles. A little bit of information will either change your mind or make you aware enough to keep you safe.
Inspection of your climbers is important. Leather straps, climber and gaffs must be in good condition. Check all pins and screws for tightness and fractures. Gaffs should be sharp and have the correct angle on them to keep you up the pole. Ask a qualified lineman or tree climber to give you hand with this. This is one of the most important things to consider as without proper equipment you are taking unnecessary risks.
Recommendations
Stay off the poles! There are just to many factors for the average insulator
collector to keep in mind. Think about this and make your own conclusion. I conclude
that this profession is a dangerous one and the people doing the job must respect
this fact. Make good decisions in your life and “Be Safe”.
Happy insulator collecting!!
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Written Saturday, December 30, 1999
Long before the modern era of computers, cellphones, smartphones, fiber-optic cables and the internet, long distance electric/electronic communication consisted primarily of the telegraph and telephone. The electric telegraph (in the United States) was developed by Samuel Morse in 1837, and the first message was sent by Morse in 1838. The telephone was invented by Alexander Graham Bell in 1876.
As time went on, networks of “open wire” telegraph lines, and later, telephone lines, were developed and built throughout the country, and these lines required the installation of insulators. Insulators were necessary by serving as a medium for attaching the wires to the poles, but much more importantly, they were required to help prevent electric current loss during transmission. The material, glass, is itself an insulator (not a “conductor” or “transformer” as insulators are often incorrectly labeled in antique malls and flea markets).
Both glass and porcelain insulators have been used since the early days of the telegraph, but glass insulators were generally less expensive than porcelain, and were normally used for lower-voltage applications. The oldest glass insulators date from about 1846.
The period from 1875 to 1930 might generally be thought of as the “heyday” of the glass insulator. Hundreds of millions of these glass “bells” were produced during this time by many glasshouses, located primarily in the East and Midwest with a few plants in California and Colorado. Many of the glasshouses that made insulators also produced bottles, fruit jars and other glassware.
Most insulators are found in some shade of aqua (blue-green) colored glass (typical inexpensive “bottle glass” or “green glass”) but many, many other color shades are found. Clear glass was used (with some exceptions) primarily after about 1935. Hundreds of different styles were developed over the years, and insulators are found with a wide variety of embossed names, initials, patent dates, and other markings.
“CD” NUMBERS
All glass pintype insulators are classified in what is called the “CD Numbering” system of identification. This system was created and used by N.R. “Woody” Woodward, an early pioneer, researcher and author in the field of collecting glass insulators. The CD (Consolidated Design) numbers basically identify insulators by their shape and profile, regardless of exact embossed markings, glass color, or base type.
For instance, “CD 154” is the CD number assigned to the most common style of glass insulator ever made, and that most likely to be seen by the average person……..the HEMINGRAY-42. Several other glass companies besides Hemingray Glass Company made the same basic model, although their versions may have raised markings, color, and base types (smooth base, sharp drip points or round drip points) that differ. But all of them would be known as CD 154s. Here’s a few other commonly found insulators: Hemingray NO. 9 is classed as a CD 106. Hemingray-10 is a CD 115. Hemingray-12 is a CD 113. Armstrong DP 1 is a CD 155. Hemingray-45 is also a CD 155. Kerr T.S. is a CD 129. There are several insulator websites that discuss this classification system in more detail.
Nearly all insulator collectors who are affiliated with the “organized hobby” of insulator collecting use CD numbers for more clarity when communicating with other collectors by mail, email, text or phone. CD numbers are used on many ebay auctions, although non-collectors who list insulators on ebay or other internet sales sites may not be familiar with the system.
Many earlier insulators have bubbles, streaking, “snow”, surface creases and other marks of crudeness which was common for this type of glass because quality standards were not usually set as high as tableware. As long as the insulator performed it’s duty adequately, the color and minor imperfections in the glass were of little concern. These “marks of crudeness and age” now add to their value and charm to collectors of antique insulators.
Old photos from around the U.S. show many telephone, telegraph and electric power poles sporting large numbers of insulators arranged on crossarms. Some telephone poles (such as in large cities) carried as many as 20 or more crossarms, each one bearing six, eight, 10 or 12 (or even more) insulators.
Each insulator was attached to the crossarm by being screwed onto threaded wooden or metal pegs, known as “pins”. A steel or copper tie-wire was attached to the insulator, and connected with the communication wire. These “pintype” insulators were an extremely commonplace sight, and communication lines with insulators were strung alongside most roads, highways, and railroads.
During the 1960s, 1970s and 1980s many of these lines were dismantled as technology advanced. Today, a few lines using glass insulators are still in service, but are only a tiny percentage compared to the heyday of open wire communication.
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Insulators (generally speaking) are still commonly in use, but insulators of the modern era (speaking of the United States in particular) are usually heavier, high-voltage types used in electric power line transmission and distribution, and are of porcelain (“ceramic”) or polymer (plastic) construction. Most modern telephone lines now make use of insulated sheathed cable, and many are underground.
Today, vintage glass insulators are a collectible item in their own right, often saved, studied and displayed along with antique bottles, tableware and other early glassware. The majority of glass insulators carry embossings (raised lettering), as previously mentioned, including company names, brands, trademarks, or model numbers, patent dates, etc. A small percentage of insulators are entirely unmarked. Perhaps somewhat surprisingly, so many insulators are found that were carefully and rather painstakingly lettered with markings that would not even be discernible by the average passersby below – only visible to linemen (and birds) !
Collectors of insulators often specialize in a particular glass companies’ products, or in certain styles, shapes or colors of insulators. They might delve into the history of a particular company, what styles where made and when, the markings used, etc. Besides the more typical “pin type” communications/electric power line insulators, other sub-categories include lightning rod insulators, radio wire or guy wire “strain” or “egg” style insulators, inside home wiring knob or spool insulators, and battery rests.
MOLDS
Many, many different cast iron or steel molds were used over the years to produce glass insulators, and the collection & study of old insulators can be compared, in some respects, to numismatics (the study and collection of coins). Most earlier insulators were made by forcibly pressing molten glass into a mold. The mold was momentarily closed, and then within a few seconds was opened and the finished insulator was removed to be placed into a lehr (cooling oven). Modern glass insulators are/were made by mass-production machine pressing methods.
On earlier insulators, many minor variations in the engravings cut into the inside surface of the molds resulted in slight differences in the exact appearance, size and placement of the raised lettering seen on the surface of the glass. On some companies’ products, more than one style of lettering can be identified. For instance, the so-called “Script”, “Prism” and “Stamp” (“Typewriter”) styles of font which are seen on many Hemingray insulators.
Sometimes an individual mold can be identified by studying and comparing insulators that were produced from it over a considerable stretch of time. Changes in the mold, such as re-cut (re-tooled) engraving, repair, or the addition or erasure (“blotting out”) of the engraving can be discovered upon very close inspection of the insulator. Thus, the comparison I’ve made to the coin collecting hobby, with the many slight differences in coin die design details, as revealed under close scrutiny by serious collectors.
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Because virtually all railroads (that were built in or before the 1950s) originally had communication lines strung alongside them (primarily telegraph, but also in some cases telephone), railroad buffs (“rail fans” or “trainspotters”) sometimes become interested in glass insulators since they were such a common sight along old railroad rights-of-way.
Railroads, trains, and telegraph lines and insulators have had a long history of being interconnected. Huge numbers of old photographs of railroads, trains and railroad-related scenes from across the United States show the telegraph lines with insulators in place – in their “original habitat”, so to speak. And modern model railroading layouts sometimes include miniature telegraph poles with tiny “insulators” to help recreate the “look” of an earlier era.
Today, most railroads in the US no longer have a telegraph line next to the tracks. But old-timers know what a beautiful sight it once was to look far down the railroad tracks and see a long, long line of telegraph poles, each adorned with glittering glass insulators, especially as seen against a setting sun!
Cleaning Insulators
Most insulators are typically found in a very dirty condition, often coated with a layer of gray or black “train soot”, or dirt and grime accumulated over many, many years of service in the outdoor environment. The underside surfaces in the skirt area are often heavily stained with a coating of stubborn train smoke. Insulators installed along railroads typically are coated, to some degree, with black soot. Sometimes the layers of soil are so heavy that the true color of the insulator cannot be discerned.
Often, new and casual collectors don’t know how to clean insulators so the true beauty of the glass can be seen and fully appreciated. Most serious insulator collectors do not keep their insulators in “as found” condition, preferring to clean them, although some collectors do keep a few pieces in their collection in their “originally found”, dirty condition just for more authenticity or “history’s sake”.
There are several ways to clean insulators, but the easiest (in my opinion) is to soak the insulator in a product that contains the active ingredient oxalic acid. Oxalic aid is usually very effective in breaking down the stubborn layers of train soot which can be VERY difficult to remove if using ordinary cleansers, soaps and detergents. Oxalic acid is an ingredient in certain brands (but not all) of so-called “Wood Bleach” or “Deck Cleaner”. (Behr’s markets their version as “All-in-One Wood Cleaner” and it does contain this ingredient). Usually, a one gallon plastic container of deck cleaner can be mixed with 2 to three gallons of water in a five-gallon plastic bucket. (DO NOT USE METAL CONTAINERS OF ANY TYPE!). Oxalic acid can also be bought in crystal form (like a fine white powder). Oxalic acid is technically a poison, so using plastic gloves when handling it is strongly recommended. (Caution: oxalic acid cannot be used to clean Carnival Glass insulators, as the carnival coating may be dissolved).
The simplest and more inexpensive method is to use the product “Bar Keepers’ Friend” which contains a diluted form of oxalic acid, and that product is sold in most large general department stores and grocery stores (usually stocked next to the cleaning products “Ajax” and “Comet”). One can of BKF can be mixed into a 5 gallon plastic bucket of water (slightly lukewarm or room temperature), and the insulators are carefully immersed and left to soak for at least 24 hours. Two days would be better. Since BKF contains oxalic acid in a more diluted form, it may or may not be as effective as other products, but it is usually a reasonably good cleaner of glass. After soaking, remove the insulators, using plastic gloves, and scrub carefully with NON-scratching cleaning pads or OOOO-grade steel wool. Most insulators will respond well to cleaning with BKF, although some may not. Some insulator collectors use lye as a cleaner, but I do NOT personally recommend it unless you are VERY, VERY careful and take ALL precautions as directed on the product label.
GLASS INSULATOR VALUES
As I’ve mentioned elsewhere on this site, my main purpose here is to concentrate on the background and history of the glassware being discussed, not on values or prices. This site is not intended as an appraisal source so little attention has been given to values. However, since the subject of values does come up often when people write to ask about insulators they’ve found, I feel that it is best to address the issue in this article.
All insulators, glass and porcelain, in my opinion, have some value. (Other collectors may strongly disagree with me on this point, but that is their prerogative). The value might relate only to the fact that a piece is an authentic relic of bygone days, or an object that can serve as a conversation piece or item of home decor.
The value may stem only from the fact that an insulator is a piece of United States history (or another country’s history) that is no longer being manufactured — a piece of “industrial archaeology”, so to speak. Or that perceived worth may lie solely in its practical value as an insulator, or that it’s still perfectly good for other uses such as paperweights or candleholders. A heavily chipped, cracked insulator with almost no monetary value to collectors could theoretically still be perfectly useable in the practical sense (as a farmer’s livestock fence insulator, or installed on a short telephone line in a rural area, for instance).
The majority of the most commonly found types of glass pintype insulators have only nominal monetary collector value, perhaps 50 cents to a dollar. That includes the extremely common types such as the Hemingray-42, Hemingray-45 and Whitall Tatum No. 1 and others. However, even within the common types of insulators, slight differences in color, embossed markings or base type can make huge differences in the market value of a specific piece to experienced collectors. A notch above the most common types will be found many insulators that range in the 1 to 5 dollars value bracket. Others are worth hundreds, and some of the rarest known insulators (some “one of a kind”) are worth into the thousands or tens of thousands of dollars.
Again, it depends on a combination of characteristics including degree of scarcity, condition, demand, age, shade of color, attractiveness, and other factors. Damaged insulators, speaking strictly of monetary value, in most cases are worth only a small percentage of the value of an otherwise identical “Very near mint” (VNM) piece. Insulators placed for sale in retail outlets such as antique malls and flea markets will, by necessity, usually be priced higher simply because of factors such as overhead – sellers typically have to pay steep booth rental fees in such places as antique malls.
The most commonly used glass insulator price guide (used by most insulator collectors) has been published for many years, in several editions, first by John & Carol McDougald, and in more recent years by Don Briel. A quick search of the internet will bring up sites where those books can be purchased.
There are other websites that discuss the general subject of values and prices. One tactic many collectors use is to do keyword searches on ebay or other internet sales sites such as Etsy. In using those sites it is best to consider only the price of a piece that actually sold (by searching “Completed Items” on the advanced search page), NOT the starting prices, “Buy it now” prices or minimum bids, as these may be set by sellers who honestly have no idea on the actual value of the pieces they are selling, and so come up with a price that is unrealistic.
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For a listing of some primary embossings found on glass insulators, and the glass factories that may have produced them: Glass Insulator Embossings.
Here are a few individual webpage articles on glass insulator companies:
List of Glass Factories that manufactured Insulators
For a list of glass factories/companies in the United States that made electrical insulators, (or are believed to have made them at some time in their history), please click here to go to my page listing those companies in alphabetical order: Glass Insulator Manufacturers
Please click here to go to my website HOME PAGE.
For a list of marks seen on bottles, fruit jars, tableware and insulators, click here to go to my alphabetical listing: GLASS BOTTLE MARKS (this points to page one).
Click here to check out my page on the so-called “Crackle Glass” insulators.
My webpage discussing recently color-altered glass, including insulators and other types of collectible glassware: Artificially Purpled Glass.
Click here for a basic summary page on WHAT IS GLASS?.
RESOURCES / GENERAL INFO CONCERNING INSULATORS
These are great sources of information posted on other websites. I would encourage anyone who has even a slight interest in glass and/or porcelain insulators to check out these websites!!
Insulators.info. Lots of good general information on Glass & Porcelain insulators and the hobby of collecting insulators!! A treasure-trove of articles and webpages on all aspects of collecting insulators! This should be your first stop on the internet for insulator-related material!
https://nia.org. (National Insulator Association) Great information and articles.
https://www.collectinginsulators.com. Rick Soller’s informational website—this site covers a lot of insulator-related “specialty” topics!
https://www.r-infinity.com/ Elton Gish’s very cool website with extensive information on collectible porcelain insulators of all types.
Porcelain Insulators – Insulators.info This link points to one of the pages on insulators.info, this page illustrating some of the markings seen on porcelain insulators. Great pics of some more unusual colored porcelain pieces!
https://allinsulators.com/ This site is a project by Shaun Kotlarsky, and is a work in progress, showing pictures and information concerning all kinds and types of insulators! Check it out!
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