Dating glass jugs

dating glass jugs

How do glass bottles age?

Early glassmakers tried their best to make uniform, quality wares; modern makers try hard to make their bottles look handblown. Perhaps the most obvious key to age is the mouth of the bottle. As a general rule, screw top bottles (except canning jars) were made after 1910 or so.

How can you tell how old a glass jar is?

Glass jars and bottles may have other intriguing marks that provide information about the jars history or age. For example, straight, vertical lines on the jar indicate it was created in a mold, because the lines represent the imprint of the molds seams.

What is a bottle dating key?

This bottle dating key is a relatively simple first cut on the dating of a bottle. While running a bottle through the key questions, the user is frequently directed to move to other website pages to explain diagnostic features and concepts as well as to add depth and/or precision to the initial dating estimate.

How can you tell the age of a 3 piece bottle?

In a 3-piece mold, a seam often runs horizontally around the shoulder of the bottle with opposing seams on the neck. To some extent, the height of the mold seam on the bottle can indicate age. However, there are plenty of exceptions to any kind of “thermometer” rule (ie. the higher the seam goes, the newer the bottle.)

How to determine the age of antique glass bottles?

When determining the approximate age of antique bottles, the first thing to know is how the glass bottle was produced. From the mid-19th century through the early 20th century, most glass bottles took shape under a glassblower’s watchful eye. However, in the mid-20th century, automation took over the glass bottle industry.

How old is a glass bottle without a rod?

In the middle of the 1800s, a snap tool was invented which let a glass blower or gaffer hold a glass bottle without a rod. This tool eliminated the sharp pontil mark (the broken end of the glass rod) at the base of a bottle. So, the lack of a pontil mark is actually a clue to age.

When were glass bottles invented?

Glass bottles have been around for centuries. It is believed that glass bottles were invented by the Romans in 1AD. Due to the rich history, glass bottles are considered collectible antiques. Normally, the older a bottle is, the more expensive it is, so it is very important to know the correct age of a bottle.

Why do old wine bottles look so old?

Bottles that are made to look old often are exaggerated in their “handmadeness”. There are huge numbers of bubbles and impurities in the glass. The glass itself is commonly thick, heavy and distorted in shape. Early glassmakers tried their best to make uniform, quality wares; modern makers try hard to make their bottles look handblown.

How can you tell how old a bottle is?

For example, fruit jars made in the third and forth quarters of the 19th century. Sheared top bottles are another case where mold seam height is not a good indicator of age. Pontil mark – A iron rod was often stuck to the base of hand blown bottles prior to approximately 1860.

Where is the seam on a 3 piece bottle?

When the bottle was removed from a mold, a faint seam remained in the glass, running from the base to a point somewhere between the shoulder on up to the top edge of the mouth. In a 3-piece mold, a seam often runs horizontally around the shoulder of the bottle with opposing seams on the neck.

What does the base of a glass bottle tell you?

The base of a glass bottle will tell you a lot about its age. In the middle of the 1800s, a snap tool was invented which let a glass blower or gaffer hold a glass bottle without a rod. This tool eliminated the sharp pontil mark (the broken end of the glass rod) at the base of a bottle.

How did the bottle-making game change over time?

In 1892, the bottle-making game completely changed with the invention of the semi-automatic bottle machine. Generally called the automatic bottle machine (or ABM), this machine molded the bottle lip along with the bottle’s body. Thus, there was no longer a need to hand-finish the bottles.

Related posts: