Just throwing in my two cents, as I have experience with mold making and casting, be very careful with all plastics and silicons in their liquid form. Always read and follow safety instructions. I was young and stupid when I started molding and casting for the first time and didn't realize that resin in it's liquid form will cause those who are exposed to it to become increasingly allergic to the chemicals in it. When I started I could touch resin in it's liquid form and be fine, now I have to wear a full face mask and two sets of gloves when I work with it. If I inhale the chemicals at all I break out in horrible rashes. If I had continued to expose myself, I would eventually need to carry an epipen and inform friends and family every time I worked with resin for fear that I would have a sever reaction and pass out or go into shock. There's a reason these things are done by experienced individuals or machines.
Also you need to keep in mind that many materials will not set if in the presence of latex. Some silicons have such vendettas against latex they won't set if you have a latex glove in the same room. It's also very costly.
That being said, molding and casting, IMO, is by far the most fun and enjoyable sculpting process and when treated with respect to the chemicals and your own body is a very rewarding skill to learn.
But again, please be careful. I'm always available by PM and can offer some knowledge on the subject of casting and molding if you ever need advice.
