Mold Marks and Pressing Methods

By John D. Gregory

Not long ago I spotted a set of three Ashburton flint eggcups at the thrift sale. These are rather common, and I was ready to pass them up since I collect mainly pattern wines. My wise wife, however, urged me to buy them, at the bargain price asked. At first glance I thought they were all alike, but a second look showed that there were very interesting differences and that the group elegantly provided evidence of certain developments in pressing methods for stemware during a specific period. The photograph shows that there were differences in size and in the exact shape of the stems.

The diagrammatic illustration shows the general outline of the eggcups with the mold marks emphasized. The cups were pressed in "two-part" molds, meaning, of course, a mold composed of two main body sections, but there were other parts: always a base and in some cases a cap ring. There are, therefore, at least a vertical mold mark on each side of the body and one around the foot. The vertical marks were neatly made to fit the divisions between the panels and are not conspicuous. There was inevitably also a mark around the rim, formed where the plunger and the mold assembly made contact. In production, this was always removed by reheating the rim, and in some cases additional tooling added a cup shape or a flare to the pattern.

Ashburton

The first, and presumably the earliest example, had mold marks extending to the edge of the rim. This indicates a mold without a cap ring. The cap ring, developed in the 1830's, was an additional part of the mold that fitted over the top of the body sections and held them tightly together. There was now a mold mark where the cap ring met the lower sections, but the vertical marks no longer ran to the rim, and the new mark could often be hidden by the pattern. The mark around the plunger, which descended through the cap ring, still had to be removed, especially on drinking vessels where it would be unpleasantly noticeable. In addition, this eggcup bears a ground and polished pontil mark on the bottom. This was the spot where the pontil rod had been attached with a bit of hot glass to provide a handle for reheating and tooling the rim of the vessel. The rod was later cracked off, and the resulting scar was often ground and polished for a neater appearance.

The second example carries a simple circular mold mark below the rim but above the body pattern. A cap ring had evidently been used, but no attempt had been made to conceal its mark. The bottom again bears the polished pontil mark.

The third eggcup has a clearly detectable, but not very noticeable, mark conforming exactly to the top edge of the pattern. The cap ring and the body sections had evidently been carefully formed in a scalloped shape to fit together precisely at the pattern top. There is no pontil mark on the bottom, indicating that this eggcup was made after the invention ofthe snap (snap rod, snap clamp, snap case) in the 1860's. This was a device on the end of a rod that could mechanically grasp the foot and hold the object firmly for further work on the rim. This cup bears several little dimples on the top of the base, and it is tempting to think that they may be marks left by the snap if it had been applied before the object was quite cool enough. I have not, however, seen any other example ofthis.

Later developments and greater sophistication ofmolds made it possible to eliminate the mold marks on the foot of stemware and eventually even on the bowl of certain forms. This required more extensive manipulation after pressing and was probably not generally economically feasible.

Pontil mark ...................................Pontil mark........................................ No mark

Schematic Diagram of Eggcups with Mold Marks Emphasized