The Hollow Rubber Stopper: Stretch It Thin to Put It In, and the Gas Seats It Tighter

"When the stopper is to be inserted in the bottle, it is first to be moistened by dipping it into water. An instrument, D, Fig. 3, made of wood, metal, or other suitable material is then inserted into the hole C, Fig. 2, in the stopper, which is placed over the mouth of the bottle, and on pressure being applied to the handle h of the instrument D the stopper is so elongated and consequently reduced in diameter that it enters the bottle freely." "To withdraw the stopper it is simply necessary to pull the portion g by the hand, by which the body i is elongated, and is easily withdrawn through the mouth of the bottle."

**Neck.** Model a block 40 × 40 × 50 mm with a bore shaped like Shaw's neck: an 18 mm mouth, widening below to 22 mm as an upper shoulder, and narrowing again to 16 mm as a lower shoulder above a 10 mm hole into the bottle. Print it in PETG and epoxy a drilled carbonated-drink bottle cap under it, holes lined up. **Mould.** Print a two-part mould for a stopper of the same shape as the bore, with a flared top above the mouth, a solid bottom and a hollow down its middle, formed by a 6 mm dowel core. Grease the mould and core with petroleum jelly. **Cast.** Mix the silicone rubber in a mixing cup as its maker directs, pour it into the mould, and leave it to cure. Cut slits into the hollow's lower wall to make it bend more easily, as Shaw's depressions n did. **Rod.** Round the end of a 6 mm dowel and glue a hardwood knob on the other end as the handle. **Test.** Fit a snap-in tyre valve in the bottle's base. Wet the stopper, set it on the mouth, push the rod into its hollow until it slips in, and draw the rod out. Wearing safety glasses, pump the bottle in steps of 0.5 bar to 2 bar and watch the stopper. Let the air out and pull the stopper out by its top.

**William A. Shaw** of Boston, Massachusetts, received US 33,964, dated 17 December 1861. His stopper had an upper shoulder a and a lower shoulder b that rested under shoulders 1 and 2 in the neck, a solid bottom f, and depressions n near its lower end to make it flexible. He listed its advantages: tight against gas, used again and again, put in by hand without mallet or breaker, and drawn by hand without a corkscrew. His claim is the hollow elastic stopper. **Honest limits.** Cast silicone rubber stands in for his vulcanized rubber, and a printed PETG neck on a plastic bottle's cap for a glass neck with shoulders. The notebook treats the rubber as keeping its volume exactly; its diameters are examples. Your seated stopper is the result.