Insulator Damage Definitions
In this section I will try and describe the various types of damage commonly found on glass insulators and the names used for describing the locations of damage. Different people will describe similar damage in a number of ways. This list is an attempt to define the terms most often used to describe the various types of damage. A list of locations where damage may occur on a the insulator, basically defines most of the common parts of a glass insulator. There is also a list of marks or defects commonly found on insulators, that are a result of the manufacturing process, rather than damage which occurs after manuafacture.
Insulator Damage Types
Here is a list of the terms commonly used by insulator sellers to describe damage to a glass insulator. I have attempted to give relative sizes, and size graduation of damage from smallest up to largest. Sometimes the nature of the damage and the location are combined into a single reference, eg. ISC which means Inner Skirt Chip, or WGC which means Wire Groove Chip or Base Flake.
The first group of items are arranged by size from the smallest to the largest, or from minor to major damage.
- Fleabite
- The smallest mark to be found on an insulator. Typicalliy less than 1/16 of an inch in size. Usually shows only as a tiny white spot on the glass. May have slight roughness if you run a fingernail over the spot. Caused by something striking the insulator.
- Bird Peck
- The second smallest sized mark to be found on insulators. Usually shows as a white spot on the glass. May have slight roughness if you run a fingernail over the spot. Caused by something striking the insulator. Slightly larger than a fleabite.
- BB-Ding
- The third smallest sized surface mark to be found on insulators. Usually shows as a white spot on the glass. May have slight roughness if you run a fingernail over the spot. Caused by something striking the insulator. Larger than a bird peck.
- Ding
- Similar to but slightly larger than a BB-ding typically about a 1/4 inch in size.
- Chip
- A small section of glass missing from the insulator. Typical chips range from 1/4 to 3/4 of an inch in size.
- Chunk
- A larger version of a chip, where a more substantial piece of glass is missing.
- Fisheye
- The result of something striking the insulator and creating a small round chip of glass that has not detached. Generally shows as a whitish circle or partial circle. A fisheye is usually fairly small, often a 1/4 of an inch or less.
- Flake
- A thin flat chip of glass missing from an insulator. Usually caused by something striking the edge of the skirt or wire groove ridge. A flake can be almost any size.
- Bruise
- A section of glass that is fractured but not detached from the insulator. Often shows as a lighter area with the associated crack or chip visible.
- Nibbling
- Areas of roughness, usually around the base, caused by numerous small chips along an edge. Sometimes excess glass "flash" from the mold was trimmed off with cutting pliers resulting in a nibbled edge.
- Stress Crack
- A fracture line or lines in the glass often found around the pin hole. May or may not be discernible on the surface of the glass by feel. Stress cracks may be caused by over tightening on the pin, swelling of a wooden pin or excessive pull or load from the wires.
- Crack
- A linear fracture in the glass. It may or may not go all the way through the glass of the insulator. Cracks may be caused by stress, impacts or rapid and severe temperature changes.
- Split
- A vertical cracking of the insulator into two or more pieces caused by freezing, stress or severe impact.
- Pop-Off
- The complete detachment of the crown and dome of an insulator. Usually caused by frost action or water freezing inside the insulator. Often results in a very smooth surface at the fracture line. The fracture often occurs at the top of the pinhole.
- Crackling
- An artificially created effect of many fracture lines and cracks in the glass. The crackle effect is created by heating an intact insulator in an oven and then plunging it into cold water. The thermal shock will cause a multitude of tiny cracks throughtout the insulator, or shatter it into a handfull of glass shards.
- Shattered
- The complete destruction of an insulator as a result of rough postal handling and/or poor packaging.
- Rust Stains
- A rusty orange-brown stain on the glass, usually in the wire groove, caused by rusting of the tie wire or the iron signal wire. Rust stains will usually come off the glass with acid soaking and some scrubbing.
- Wire Rub
- A dull, worn mark usually made in the wire groove or saddle groove by the action of the tie wire, signal wire or cable rubbing on the glass as the wire moved in the wind.
- Glass Sickness
- A dull, milky coating on the surface of the glass usually found on insulators that have been buried in the ground. Cleaning and soaking generally will NOT restore the surface. Valuable insulators are sometimes tumbled to restore the surface shine.
Copyright © 2007 - Doug Netzke and Micro Solutions of Sudbury