Naked shoot out fun!
The mold has been poured and now we wait. I waited about 5 hours, but I'm paranoid. The box says the hydrocal will set in 1 hour, and my professor who has a great deal of experience says 20 minutes, when the hydrocal is warm, it'll be hard enough to remove and the clay will come off easier. But, I waited 5 hours.
When you're content, pull the foam core walls off, you can tear them and destroy them if a want, but they could potentially be used a bit later. The walls are gone, now flip the mold and foam core (that's on the bottom of what used to be the box.) Carefully remove the foamcore. Now you will see your sculpt (which should be exactly in the mold still; if it has come out you're screwed and will never get it perfectly registered again) and the sculpt is surrounded by the green Klean Clay.
Carefully remove the green clay. Try to get big chunks and pull from them. Make sure to not remove the sculpt with the green Klean Clay. Once you've removed the big chunks there'll be little bits still on the mold and right next to the sculpt. Some of these bits are very important to clean. Try to get as much off as you can, but if there's any touching or close to your sculpt you need to get that off otherwise your cast could have something wrong with it. Also if there is some near the key you need to remove it, but with a large key it shouldn't be a problem if there's a little left.
Also remember to take the bolts out. I had to screw them out, I couldn't just pull them out. This is fine. When you are have the bolts out cover the hole with some klean clay. Make sure there is a seal, nothing can get in. This is so that in the unlikely event that the liquid hydrocal for the second part of the mold gets down to the side of the walls, it wont fill that hole and harden.
I left the green klean clay that was by the neck on and added some more. I want there to be a pour spout on the top of the mold.
Okay, once all of the green clay is gone we need to prep for the second part of our two part mold. First you should make the walls, but do not attach them. Make them the same way, measuring the sides and cutting. Eventually we will attach them with hot glue and seal up the sides and cracks with hot glue.
Now, we need a releasing agent for the mold part that has now hardened. For this we need Vaseline, or any kind of petroleum jelly. Very generously lather on vaseline to the hardened hydrocal. Do this not only on the surface that used to be touching the green klean clay, but on the sides as well. This is so that in the unlikely event that the liquid hydrocal for the second part of the mold gets down to the side of the walls harden and attach to the first part of the mold. Make sure to vaseline the edges and around the key a lot.
Now put on the walls that have already been cut. When I did this, I put on the vaseline before i measured and cut the walls, it created a messy annoying problem.
So you have vaseline on the 1st mold (don't put it on the sculpt.) The walls are up and glued to each other and the foam core base. There are probably some gaps between the wall and the hardened hydrocal mold. Fill this crack with either clay or glue. I used hot glue because it's easy.
Okay, draw your fill line on the interior of the wall again like I did in the first pour and mix/pour again using the same techniques.