Molding, Part 4

The next step gets the mold off the clay model and ready to cast. I begin by removing the cabinet. I didn't tell you earlier that the cabinet is held together with large wood screws. I unscrew one end, pull that end off, and remove the rest of the cabinet from the mold.


Now the part that always worries me. I have to separate the two halves of the mold. No matter how much clay and Vaseline I use, the seam is always bound by a thin layer of plaster that seeps down during the setup process. My concern is that when separating the two halves I'll break the mold. Then, if the clay model is damaged, I'll have to start over. I always worry about it. But it's never happened.

To separate the two halves, I tap around the seam with a chisel to loosen that thin layer of plaster. Then I gently drive the chisel into the seam at a really thick place. The two halves separate easily. And I sigh a big sigh of relief.


The next step in the mold-making process is to remove the clay model from the front half of the mold. Depending on undercuts, this process can destroy the model. This time, however, Uncle Sweeter's head lifts out effortlessly. His nose got out of joint, but when I pushed it back into place, there he was, good as new. Now, if anything goes wrong with the mold from here on, I can make another one. Whew.


The last step is to clean up the mold so I can begin casting. Cleaning involves removing any plaster particles and clay that stayed behind when I removed the clay model. I can also patch any serious imperfections with spackle.

I do casting outdoors because of the toxic nature of fiberglass resin. Just now we are enjoying the edges of Tropical Storm Alberto, the first significant rain we've had this year. Casting will have to wait until the skies clear. Check back in a day or two.