Laying Up Your Clay:
Before you start molding your sculpture it is a good idea to seal it. I sprayed down my little troll here with crystal clear (found at any hardware store) and let it dry before starting to mold. I also filled in the holes where the arms meet the shoulders, where the square stock piping from the arms inserted. The clay that I'll be using here is a water based clay (found at any art store). During this part of the mold what I'm doing is sculpting the opposite side of the mold; remember that everything that is clay here will be silicone soon. I'm creating a clean crossection of my sculpture. Start out by roughly laying in your clay keeping it as flat and level as possible following the contour of your sculpt. Try to keep everything as clean as possible and try your best to keep the clay off your sculpture. The reason that I sealed the sculpt is- if I do get clay on the sculpt (and I will) I can use a brush and some water and clean it off easily. Remember, even if you are as clean as possible, clay is still sitting against the back of the sculpture and that clay will need to be cleaned off eventually, so seal your sculpt before you begin.

Smoothing Out Your Clay:
Once you have roughed out your clay, grab yourself a tool to smooth it out and make sure that the clay is going right against the sculpture. You want the water based clay to be right up against the sculpt (no gaps allowed). You can see in the picture to the right that I'm making the clay as level as possible and it comes right up against the sculpture. This is one reason that I like working in Super Sculpey and Premo for my sculptures. It is much easier to mold something hard than something soft. If I sculpted this sculpt in soft clay (unhardened clay) then when I'm using my tool right up against the sculpt I could accidentally nick it. You can also clearly see (right picture) why I sculpted the arms to be separate pieces. If the arms were attached the 2 mold pieces could not be parted without cutting the silicone, because the right elbow is below the armpit. It Is Important to be as precise and neat with this step as you can. If you are sloppy with this step you will end up with a sloppy mold.

Water and a Brush:
Next go in with some water and a brush and smooth out your clay even more, especially up against the sculpture. Here is where you define a really clean parting line. If you get some clay on your sculpt just rinse it off with a clean brush and some water. A clean parting line is very important because once you get to casting your sculpture you are going to have a seam line to clean up (on your casting), and the smaller that it is- the easer it will be to clean up. A neat and clean parting line will give you a good seam on your castings.