Most bottles made in the United States before the 1850s, when the snap case tool virtually replaced the pontil rod (also called the punte or punty), have a pontil mark on their bases. The mark is formed when a bottle is transferred from the blowpipe to the pontil rod, which, unlike the blowpipe, is solid. Known as empontilling, this transfer allows the glassblower to form and finish the bottle’s mouth or bore. Though no longer used in glass manufacturing, this technique is still used in art glass today.
The hand off from pipe to rod can be tricky. If the pontil rod is not attached firmly enough to the base, the bottle will crash to the floor when it is separated from the blowpipe. If the connection to the pontil rod is too strong, the base of the bottle can shatter when the glassblower attempts to crack off the finished bottle from the rod.
Different empontilling techniques produce different types of pontil marks and scars on the bases of bottles. For example, when the end of a pontil rod is covered in molten glass, which is used as the glue between the rod and the bottle, a scar may be produced when small flakes of the bottle’s base break off and remain on the pontil rod, causing a slight depression in the base. In other cases, jagged fragments of glass at the end of the pontil rod sometimes stay attached to the base. If these imperfections are small, the bottle may be left as is, but if the defects could cause a customer to cut a finger, the base might be sanded before being shipped.
Another technique practiced in the middle of the 19th century involved heating the pontil rod until it was hot enough to fuse to the bottle’s base. The primary advantage of this bare-iron technique was that it saved time and labor, eliminating the need to gather and form the piece of glass at the end of the pontil rod. Indications that a bare-iron pontil rod was used include a rusty residue on the base of the bottle. Sometimes this mark is disc shaped, other times it shows up as a ring.
For glassblowers who were working without assistants, the blowpipe was often pressed into service as a pontil rod. This technique required a great deal of skill because the glassbower would have to work very quickly to set the bottle down so it laid flat, crack off the blowpipe, quickly gather more molten glass at its end, and then re-attach the blowpipe to the base of the bottle. If the glassblower took too long to accomplish these steps, the bottle could cool too much, which could cause it to crack. For this reason, some glassblowers probably just had assistants bring them a nearby blowpipe that was used instead of a pontil rod.
One interesting variation on the glass-tipped pontil was the sand pontil, in which the molten glass at the end of the pontil rod was rolled in sand just before being attached to the bottle’s base. This allowed the pontil glass to adhere to the base, while the sand acted as a kind of perforation, making it easier to remove the bottle from the pontil rod. Scars left by sand pontils are generally wider than those left by glass-tipped or bare-iron ones.
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