I use silicone mold making compounds for small craft projects like jewelry and doll faces.
One thing to remember when pouring silicone is to think about the size of your project. Depending on what type of silicone compound mixture you use, you may not have a lot of time before the mixture starts to get hard.
This is fine if you are working with small pieces, but if you have a large project, you need to use something that gives you more time.
I have also learned not to rush the amount of time you let your mold sit and get completely hard. This was one of those things that was learned the hard way.
The temperature and humidity can make a big difference, so I always allow enough time for the mixture to be set all the way through.