Friday, July 17, 2009

Detachable Plates for Glass Molds

Have you ever wondered why two of the bottles you own have different embossing but look like they were blown in the same mold. Well - that's because they were !!!!
Back in February of 1875 Gustavus Storm applied for, and was granted in May of the same year, a patent for Improvement in Detachable Plates for Glass Molds.
Gustravus didn't invent the slug plate he just made improvements to the original concept, stacking several plates together and venting the plates for air to escape when the molten glass was blown into the mold.
This improvement allowed the glass houses to carry a "standard mold" for a particular style of bottle, for instance, a medicine mold, beer mold, bitters mold and so on.
The detachable slug plate was then engraved to the clients specifications - for example -

Take a look at the Taussig and Mott's bottles pictured at left. Sure looks like an identical mold with different embossing to my eyes.

The side view of the bottle mold in Figure 1 shows how the slug plate sits in a hollow in the mold. Note the rivets holding several plates together.
Each plate could possibly hold from one to several engraved letters.

Figure 2 shows the engraved plates in the bottle mold. Notice how the engraved letters are backwards on the plates. Ever wonder why some bottles have a backwards letter in the embossing.

The top view of the bottle mold in Figure 3 shows the detachable slug plates sitting in the hollow of the mold.
Figure 4 shows the "stacked" plates before being engraved. Rivets hold the plates together

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