For many years, silicone rubber had to be mixed and heated in very strict conditions in a process called vulcanization, and these conditions were difficult to replicate at home. The invention of RTV (room-temperature vulcanization) silicones has changed this, allowing homemade projects to be made out of silicone rubber. These RTV silicones can be purchased at a number of art and industrial suppliers. Unformed silicone rubber isn't very interesting, so you usually pour these ingredients into a mold to make a figurine or other shape.
Things You'll Need
Mold, cookie sheet or other container
Set a paper bucket onto a scale and reset the scale to zero.
Pour some silicone base into the paper bucket and weigh it. For the most accurate mix, you should weigh the base in either ounces or grams.
Add the correct amount of catalyst to the base. Most silicones use a 10:1 ratio of base to catalyst, but check the label on your silicone to make sure. If the ratio is 10:1, simply divide the base weight by 10 to determine the amount of catalyst to use. For example, 74 grams of base requires 7.4 grams of catalyst.
Mix the catalyst into the base completely. Most silicone bases are white, while the catalyst is dark blue or green, allowing you to visually ensure the two components are mixed. Scrape the sides and bottom of the bucket several times as you work. Take your time -- most RTV silicones take several hours to cure.
Pour the silicone into a mold, cookie sheet or other container to cure. If the container is made of silicone, you must first brush on a thin coat of hand soap as a mold release. Otherwise no release is required.
To avoid air bubbles in the cured silicone, pour the silicone from high up very slowly. The air bubbles will break as it drizzles down.
Do not wear rubber gloves, as the rubber can inhibit the silicone from curing. Instead, wear gloves made of vinyl.