Mark Wasteney
Vulcanite Screw Bottle Stopper
Macro Mondays 22/04/19 theme.Bottle Cap
I found this bottle and stopper years ago on a rifle range and assumed the war grade on the cap referred to the substance inside but I have now found out it relates to the stopper itself.The screw stopper is made from vulcanite which is rubber that through the process of heating (vulcanisation) at 115 degrees Celsius and with sulphur and linseed oil added produced a durable hard rubber material.During the 2nd World War rubber was in short supply due to the Japanese invasion of Malaya and Dutch East Indies. Due to the need for rubber for gas masks, gaskets, tires and thousands of other military uses the humble stopper was made of poorer quality materials with less rubber than pre-war examples and marked War Grade.In other examples there is also a dip in the top which saved even more rubber.
hatchfive.wordpress.com/2015/06/08/war-grade-beer-bottle-...
Vulcanite Screw Bottle Stopper
Macro Mondays 22/04/19 theme.Bottle Cap
I found this bottle and stopper years ago on a rifle range and assumed the war grade on the cap referred to the substance inside but I have now found out it relates to the stopper itself.The screw stopper is made from vulcanite which is rubber that through the process of heating (vulcanisation) at 115 degrees Celsius and with sulphur and linseed oil added produced a durable hard rubber material.During the 2nd World War rubber was in short supply due to the Japanese invasion of Malaya and Dutch East Indies. Due to the need for rubber for gas masks, gaskets, tires and thousands of other military uses the humble stopper was made of poorer quality materials with less rubber than pre-war examples and marked War Grade.In other examples there is also a dip in the top which saved even more rubber.
hatchfive.wordpress.com/2015/06/08/war-grade-beer-bottle-...