Why do glass bottles have seams?
From about 1920 on, most wineglasses have been manufactured in a process where a two-piece bottle mold clamps around liquid glass. Air is then blown into the center so the end result is a hollow but formed glass bottle. That means that yes, bottles will have two seams that run from the top to the bottom of the bottle.
When did glass bottles start to have seams?
If the seam extends only part way up the neck, the bottle was most likely formed between the late 1700s and the early 1800s. No seam indicates a handblown glass bottle that predates the use of molds in bottle making.
How can you tell if a bottle is antique?
This is usually a clear identifier of an antique bottle. Check the bottom of the bottle for what is known as a pontil mark. This will be a ring or area of rough glass from where a supporting rod held the bottle during glass blowing and definitively dates the glass as being vintage.
Why do bottle molds have seams in them?
OF BOTTLE MOLDS: This miniature toy mold (made of clay instead of iron), shows why/how the bottle seams (running down on either side of the bottle) come into being. No matter how snug or tight the fit between the two sections (and in some cases three) of the mold, there’s always a rough edge where they make contact–thus creating a seam.
How can you tell if a glass bottle is handblown?
No seam indicates a handblown glass bottle that predates the use of molds in bottle making. This is usually a clear identifier of an antique bottle. Check the bottom of the bottle for what is known as a pontil mark.
Where does the seam in a glass bottle come from?
Seam rises completely to the top of Bottle At the height of the industrial revolution, glass manufacturers quickly adapted mass production techniques — instead of molding or shaping the whole bottle by hand in the open air, as was originally done. It was found that by blowing the molten glass into prepackaged molds greatly simplified the process.
This is usually a clear identifier of an antique bottle. Check the bottom of the bottle for what is known as a pontil mark. This will be a ring or area of rough glass from where a supporting rod held the bottle during glass blowing and definitively dates the glass as being vintage.
What’s the seam method for dating glass bottles?
THE SEAM METHOD – OF DATING OF GLASS BOTTLES 1840 – 1860* Seam verily goes over the shoulder 1860 – 1880 Seam rises onto the neck of the bottle 1880 – 1900 Seam completely goes up the neck After 1900 Seam rises completely to the top of Bottle
OF BOTTLE MOLDS: This miniature toy mold (made of clay instead of iron), shows why/how the bottle seams (running down on either side of the bottle) come into being. No matter how snug or tight the fit between the two sections (and in some cases three) of the mold, there’s always a rough edge where they make contact–thus creating a seam.
