Welcome to all our guests. Take a look around and we hope you decide to join us.
0 Members and 1 Guest are viewing this topic.
Dating jars.There are several ways to date an antique jar or bottle. Probably the most important is the presence or absence of a pontil scar. The pontil scar - a ring of glass or a black and red iron-like indention on the base of a bottle or jar - indicates that a glassblower held the item on a pontil rod (when the glass was hot) while the neck and/or lip was shaped and finished by hand. Typically, American pontil scarred bottles predate 1855 or so.Another age determiner is the presence of mold seams. Many of the earliest bottles or jars were freeblown (that is, blown without the aid of a mold) therefore have no mold seam. Seams which stop short of the lip indicate that the bottle was blown into a mold then finished by hand by adding a top or tooling the lip into shape. Machine-made jars (dating after about 1915) have mold seams extending from the bottom up to and across the top of the jar.Another way to tell the general age of a jar is to examine it from top to bottom. Is the top smooth to the touch or is it rough and ground off? Look at the base of your jar. If the base of your jar has a round ring in it and the lip is smooth, your jar was probably machine made sometime after the turn of the century but probably before the 1930s. If the jar has a large, rough and jagged ring on its base, it was probably made between 1900 and 1930 when the Owens machine was in popular use. Machine-made jars after the 1930s have a more modern look and frequently have small scars on the bottom indicating they were made on more modern, sophisticated machines.Most jars with rough ground tops were made before 1900. The ground lip resulted when the glassmaker ground the top to eliminate the "blow-over." The blow-over was a gob of glass at the top of a jar that the glassblower used to attach a blow pipe when the jar was blown by hand into a mold. The blow-overs were removed and the top was then ground flat.