RemakingHistory-Rubber-1-co

Charles Goodyear may have been the most dogged and unrelenting solo inventor of the 19th century’s golden age of invention. His was an interesting life, a wild roller coaster of ups and downs, although unfortunately mostly downs.

Goodyear was not wealthy or wildly successful. Many people are surprised to learn that he did not start, work at, or even know of the giant industrial concern called the Goodyear Tire and Rubber Company. The company, which was named in Goodyear’s honor, was founded in 1898, about 40 years after Goodyear died.

The Early Years of Rubber

In the winter of 1820, a rubber fad swept across America when millions of people bought rubber-coated boots to keep their feet dry. But the fad ended as abruptly as it started when consumers found that a single summer of hot weather turned their rubber shoes to mush. Natural rubber clothing just wasn’t durable or practical.

At that point Charles Goodyear entered the scene. Goodyear thought that if he could figure out a way to toughen the rubber chemically he would have a product that people would buy. Although he knew almost nothing about chemistry, engineering, or business, he was, like the substance he was trying to make, resilient and tough.

He began to experiment with latex. He mixed in witch hazel, magnesia, even cream cheese in attempts to turn sticky, soft latex into durable, tough rubber. Nothing worked. He got close a number of times, but was not able to develop a repeatable process that would turn rubber into a useful raw material.

He kept trying until he had spent all his money, so he borrowed some. He spent that and borrowed more. Eventually, he and his family were broke and living on the charity of his friends. Things looked bleak.

The Lucky Accident

Then an accident changed things. On a cold winter day in 1839, Goodyear inadvertently brought a piece of rubber that he had treated with sulfur into contact with a hot stove. The inventor looked at the piece in amazement. The hitherto gummy yet fragile compound had become something wonderful.

Goodyear’s rubber fragment did everything that natural latex could not. It had become, in modern parlance, vulcanized. It was tough and durable in hot weather, and stayed flexible in cold weather. This, Goodyear knew, was a product with a huge future. By the winter of 1841, things were looking up. Goodyear’s new process was an astounding success, and money started to come his way.

But sadly Goodyear was not a capable businessman. While he did obtain a patent for the vulcanization process in 1844, he licensed the process at rates that were far too low for him to make money. Worse, when patent infringers stole his work, he spent more on his attorney’s fees than he was able to recover from the pirates.

He spent the rest of his life attempting to make good his dream of becoming a millionaire rubber manufacturer. Goodyear staged magnificent displays showcasing rubber products including furniture, floor coverings, and jewelry at London and Paris exhibitions in the 1850s. But while in France, his French patent was can-celled and his royalties stopped, leaving him with outstanding bills he could not pay. Goodyear was thrown into a debtors’ prison.

When he died in 1860, Charles Goodyear was $200,000 in debt. Posthumously, royalties on his process started to roll in. His son Charles Jr. later made a fortune manufacturing shoemaking machinery. It’s a shame that Charles Sr. never enjoyed the financial success his invention ultimately provided for his family.

Make a Rubber Eraser

You can re-create the process of vulcanization using a modern product to make your own rubber items, like these pencil erasers in a shape you might recognize. We think Mr. Spock would appreciate them.

1. Determine how much Pliatex, water, and vinegar are needed to make your erasers by calculating the volume of the mold. You need to use enough liquid ingredients to fill twice the mold volume for each eraser because the solidified rubber occupies considerably less space than the liquid ingredients.

2. Mix equal amounts of water and Pliatex in a bowl and stir until smooth. You can add food coloring to the final product if desired.

diagram-2---pliatex-and-wat

3. Measure an amount of vinegar equal to the amount of water used and place it in a bowl.

4. Add the Pliatex-water mixture to the bowl with the vinegar. Stir briefly until the solution congeals into a cheesy, soft mass.

diagram-3---add-solution-to

5. Working quickly, place the rubbery mass into the eraser mold and press firmly. Pour off the surface water and press firmly again. Pour off any pooling water that appears on the surface of the mold.

diagram-4---pour-into-mold-

6. If you simply let the rubber harden in the mold, it will turn into a harder, tougher eraser.

7. If you want a softer, more flexible eraser, place the mold and eraser compound in a 300°F oven for 10–15 minutes, depending on the size of the mold.
diagram-5---bake-copy
Remove and let it thoroughly dry. Your eraser is ready for use!
diagram-6---finished-eraser

From a chemical standpoint, what’s happening is this: Pliatex is a partially vulcanized latex rubber compound called polyisoprene. It will naturally begin to coagulate and harden on its own unless it is stored in an alkaline environment. So, the manufacturer adds ammonia to keep the pH level high during storage. When you take the cap off the bottle, you’ll smell the ammonia used to preserve it.

When you add vinegar to the solution, the acetic acid in the vinegar quickly lowers the pH, and the large polymer molecules in the latex come out of the solution to complete the vulcanization process and form a solid piece of rubber.

diagram-1---tools-and-mater