2. FIND OR MAKE A MOLD CONTAINER
You’ll need a paper or plastic cup, or a yogurt or other food container ¼" to
2" larger than your master
pattern on all sides. More than
2" of space around the object will only waste material and make the mold
less flexible. If you can’t find an existing container that’s slightly bigger than your object, construct a box
out of cardboard, sealing all seams with a hot glue gun so the container doesn’t leak.
3. MAKE THE MOLD
Glue the flat side of the master pattern to the bottom of the container
to keep the object from floating when you pour in the silicone. Draw a
line on the container to indicate where the back of the object is positioned, because once the silicone is poured in, you won’t be able to tell
back from front. Later you may need to cut the mold in order to remove
the object, and a cut will be less noticeable at the back.
To pre-measure the silicone, pour some uncooked rice into the container
until there’s a
2" layer of rice on top of the object. Pour the rice out
into a measuring cup: this is the amount of silicone you’ll need.
When you purchase the silicone, the package will have 2 bottles: the
silicone and the catalyst. Thoroughly mix the silicone and catalyst
together to make the amount you need; immediately they become
activated and the slow hardening process begins.
Pour the mixed liquid silicone around the object until it covers it by
2". Tap the mold gently on a work surface to remove the air bubbles.
(Alternatively, you can remove the bubbles by placing the mold on top
of a running clothes dryer loaded with a few tennis balls for 30 minutes,
or you can put it on top of a stereo speaker with the bass cranked up for
30 minutes and dance until the bubbles are gone.) Then let the silicone
cure for 12– 24 hours, or as directed on the package.
Mark a line on the hardened silicone that aligns with the line you drew
on the container to indicate the back side of the object. Rip or cut the
container away from the mold. Remove the master pattern; it might
pop right out of the mold, but if you have trouble removing it, use a
utility knife to cut a small slit in the backside of the mold to create an
opening. Wash the mold with soap and water.