Step 5: Pouring the silicone

Mix the silicone according to the directions provided. Pay careful attention to whether it asks to measure by weight or volume.

Pour the silicone mix over the wooden blocks, filling the housing to the rim.

Let set according to the directions provided (usually it will be at least 10 hours).
vt130138 years ago
Did you tap or vibrate the mold to make sure you didn't have any air bubbles? I noticed a few on the pour images.
Tetranitrate (author)  vt130138 years ago
I tapped it a few times to get rid of as many bubbles as I could.
Mixing the silicone very slowly will also help with air bubbles, check the cure time of your rubber first though, most have more than enough time to be patient when mixing. Ideally you would make a vacuum chamber and vacuum the rubber before pouring it. but be sure not to fill your container more than 2 thirds or less or you'll end up with silicone all over your vac chamber! gooey mess!
it also helps to use an old brush to paint a layer of silicone over the surfaces, especially where there are overhangs, before pouring the rest
make sure you use food grade silicone
Omegablood7 years ago
Where do you get the silicone to make the negative mold?