Insulator Damage Definitions (continued)
Manufacturing Defects or Marks
This section defines the various marks and defects that are found on insulators as a result of the manufacturing process, rather than actual damage which occurs after manaufacture, either when the insulator was in use, or in subsequent handling, or transport.
- Blot-Out
- Old embossing on a mold that was attempted to be removed; however there are traces of the old embossing still visible.
- Bubbles
- Air bubbles that were trapped in the glass during the pour. Bubbles may be almost any size from minute up to an inch or larger.
- Cold Pour
- A situation where the mold was not up to proper temperature before the glass was poured into it. It results in the glass cooling too quickly and often not flowing properly into all parts of the mold. Cold pour insulators often have multiple straw marks.
- Fizzy
- A multitude of minute air bubbles that were trapped in the glass during the pour. A truly fizzy insulator has the appearance of a glass of soda or champagne.
- Flash
- A thin ridge of glass usually found along the mold lines, caused by improper mating of the mold parts, allowing glass to ooze out into the joint during the molding process. Flash is sometimes ground off at the factory, leaving a rough, dull area.
- Ghost Embossing
- Faint embossing that may appear on the insulator due to initial contact of the glass with the mold before the insulator is fully formed. Often the ghost embossing is near the regular embossing, but there are cases where phrases from the skirt are ghost embossed on the dome.
- Grinding
- An area where irregularities in the molded insulator have been mechanically ground off at the factory leaving a dull, rough area. Often used to remove excess glass "flash" from the mold lines, or base. Very common on the "shoulder" areas of French gingerbread style insulators.
- Junk in Glass
- Foreign objects that were in the mold or stirred into the molten glass that find their way into the finished insulators. Examples of junk in glass include nails, bits of wire, pieces of fire brick, stones, and even coins. Some people specialize in collecting insulators with junk in the glass and often pay premium prices for good examples.
- Leaner
- An insulator whose base is not properly formed causing the insulator to lean when placed on a flat surface. May be caused by slumping or an underpour as well.
- Open Bubble
- Sometimes a bubble would form in the glass at the edge of the skirt or base. The overlying surface glass of the bubble breaks away leaving an open hole into the insulator.
- Out of Round
- An insulator that is not round when viewed from the bottom.. Often caused by the insulator being gripped or handled with tongs while the glass was still too hot and semi-soft.
- Overpour
- The result of too much glass being placed into the mold during pouring resulting in excess glass oozing out around the edge of the base. The resulting glass flash is sometimes trimmed of with pliers/cutters at the factory resulting in a nibbled edge on the skirt.
- Rack Marks
- Marks appearing on the base of an insulator from where it sat on the wire racks in the annealing oven. Most likely caused by the insulator being moved from the mold to the wire racks in the annealing oven too soon after pouring. Marks are often visible on several areas of the base, with the marks on one side lining up with the marks on the other side.
- Slumped
- An insulator that is shorter and usually wider than normal having softened and slumped down while in the annealing oven. Could be caused by removing the insulator from the mold too soon after pouring.
- Straw Marks
- Shallow, often wiggly lines which look somewhat like creases that occur on the surface of an insulator. They are caused by the molten glass contacting a mold that is not hot enough, causing the glass to cool slightly, preventing the glass from flowing smoothly and conforming completely to the shape of the mold.
- Tong Marks
- Marks visible in the sides of an insulator from the tongs used to pick up the insulator after unmolding to be be placed in the annealing oven. Most likely caused by removing the insulator from the mold too soon after pouring.
- Underpour
- The result of not enough glass being placed into the mold during pouring resulting in incomplete molding of the base, skirt or inner skirt. May also result in incomplete formation of drip points on the base.
Copyright © 2007 - Doug Netzke and Micro Solutions of Sudbury