Pour spout and air vents:
This was a non issue with the body of our little troll here because the bottom of the mold is open and I poured the Silwhite down one of his legs and the air escaped out his other leg. With the arms of the troll I cut a pour spout and the air vents into the silicone with a razor blade (mouse over left picture). When you are selecting where to place your pour spout the first thing you need to concern yourself with is where air bubbles might get caught in your mold. You can see that I decided to pour into the elbow on both of the arms. The elbow is a high point on both arms and is the ideal place to pour into the mold in order to avoid air bubbles being caught in the fingertips. Air vents are important because when pouring your material into your mold the air needs a way to leave the mold. If you have a small pour spout (like on these arms) your air vents need to be separate from your pour spout. I'm casting in Silwhite here and Silwhite sets up very quickly witch means that I need this pour to go quickly, and the air to escape quickly.

Cleaning Up Your Seam Line:
After you de-mold your casting you will notice that there is a seam line to clean up. If you have a good clean mold this step will be done in no time, however if your mold is less than perfect this step can take a lot of work. A clean seam can be cleaned up by scraping it with an exacto knife (pictured to the right). If the seam on your casting is a little thicker, then use an exacto knife and some small files to grind that seam line down. When trimming down your seam line be careful not to grind away your sculptures detail, just the seam. Once you finish trimming down your seam, look at it in harsh scraping light to ensure you got everything.

Preparing Your Pieces for Assembly:
Next we will be putting the arms on our little troll here. When you assemble your pieces you "can" just super glue them together and patch the crack, but I like my castings to have a strong bond that will last. To create a strong bond first drill a large hole in the center of your casting on both sides (to fit your threaded pipe). Then drill smaller holes around the big hole (on both sides) with varying direction, this will help lock the pieces together (pictured to the left, mouse over for zoom). Next, lightly sand the area so that it's not perfectly smooth. Finally cut yourself a piece of threaded pipe to fit into your larger holes. I will be using Bondo (found at any hardware store) as my bonding material. I use a threaded pipe so that the Bondo has something to grab onto. This setup will take a little extra time but if you ever drop your casting or pick it up by the arms, it won't break apart. This is especially important if you are selling your castings, nobody wants to buy sculptures that break apart (I sure don't).