Made my first own vulcanized rubber, basically from latex milk, sulphur, zinc oxide and a few drops of Fairy dishwasher soap (non ionic tenside). The soap helps with the mixing, the zinc accelerates the process. But it is the sulphur that does the magic: It builds bridges between the long polymer molecules. Just 30 minutes in a normal cheapo kitchen oven (bought for 50 Euros on the web), and tt does work! Rubber as we know it. It stretches, it is dry, and it snaps back just fine. The only issue I ran into: I stirred the ingredients to hard, which causes some foaming up (likely due to the soap drops). Next batch, more careful stirring - fewer bubbles. The results are VERY ENCOURAGING - a stable product, it stretches to the familiar factor of 6:1 before it tears. Very snappy, too! More experiments ahead.