Frequently Asked Questions (FAQ)  

This page answers frequently asked questions about Hemingray insulators.

If you have a question about insulators in general, please read the FAQ.

1. Was my insulator manufactured by Hemingray?
Many different companies manufactured insulators. Refer to this chart to see if your glass insulator was manufactured by Hemingray. Hemingray ONLY manufactured glass insulators (not ceramic, porcelain, rubber, or plastic.)

2. How much is my Hemingray insulator worth?
That depends on several factors, including CD number, condition, color, and embossing! Please refer to the Find Your Insulator's Value page for more information.

3. Which Hemingray insulator do I have?
If your Hemingray insulator is embossed with a style number (such as HEMINGRAY-42 or Nº16), you can look up your insulator by style number. Otherwise, try the Identify Your Insulator page.

4. What do the numbers on my Hemingray insulator mean?
If the number is directly after "Hemingray" (such as Hemingray-42 or Nº16), that is called the insulator's style number. Some Hemingray styles are comprised of letters, words, or a combination, such as: T.S., E2, Nº1 Provo Type, Muncie Type, etc.

Newer Hemingray insulators (produced after 1933) also have mold numbers and date codes, such as "20-46::". Refer to this page for more information on how to decypher these numbers.

5. How do I clean my Hemingray insulators?

I clean my dirty insulators in a 5 gallon plastic bucket of water with oxalic acid (wood bleach crystals) mixed in. A good ratio is about 1 pound of oxalic acid for every 2.5 gallons of water. This mixture lasts for many years (my bucket has been used for 7 years and has cleaned dozens of insulators with no problem). Using rubber gloves, place your dirty insulators carefully into the bucket and let them sit for several days (or weeks if you're not in a hurry). Once they're ready, remove the insulators, rinse them off under cool water, and use 00 or 000 steel wool to get off any remaining soot. Especially stubborn insulators can go back into the bath for another round.

There are many important notes to observe before working with oxalic acid!
• Add the oxalic acid crystals to the water (not vice versa).
• Use a plastic bucket (not metal). Oxalic acid is corrosive and will eat away at metal.
• Always wear eye, face, and hand protection. Even though it's a mild mixture, be safe.
• Keep the bucket out of reach of children and pets. Always keep a lid on it when not in use, and label the bucket.
• Never use oxalic acid to clean carnival glass, flashed amber, opalescent glass, or insulators with metal pieces attached.

For more information and other insulator cleaning techniques, please visit

I assume no responsibility for any misuse or damage caused by the information above.

6. What are those "bumps" around the bottom of my insulator?
Those "bumps" are called drip points. Hemingray patented drip points on May 2, 1893 as "teats" for drawing moisture off of the insulator. Hemingray produced two styles of drip points: sharp drip points (1, abbreviated "SDP") and, later, round drip points (2, abbreviated "RDP"). Some later Hemingray insulators were also produced with a corrugated base (3, abbreviated "CB")—a rough, cross-hatch style base which is not considered a form of drip point, but essentially served the same purpose. Hemingrays were also commonly manufactured with a smooth base (4, abbreviated "SB").

7. Where can I buy Hemingray insulators?

Hemingray ceased operations in the 1970's, so if you're looking to buy Hemingray insulators to start your own collection, I would highly recommend joining the National Insulator Association and looking for an insulator show in your area. This is the best way to get in touch with other insulator collectors. You'll also find that we insulator collectors are very generous and might even give you an insulator or two to get started! We love encouraging new collectors in the hobby. eBayis also a good place to find Hemingray insulators, though you'll be paying more in shipping.

8. Where can I sell my Hemingray insulators?

If you have an insulator that is on my Wanted List that you're looking to sell, please contact me!

Otherwise, if your Hemingray insulator is worth $5 or more, is generally a good place to start. On the other hand, if you're looking to sell a box full of very common $1 insulators, you're better off just donating them to a local antique/junk/thrift shop, giving them away to kids, or using them as indoor/outdoor decorations. and see how many other people out there have the same insulator you do and how much they're selling for (and, more importantly, if there are any bids!)

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