Step Four – Foaming, Foaming, Foaming

Making support molds for silicone covered heads.

I completed the support mold by standing one of the silicone and sports-mesh covered heads in a waxed, upside-down bucket with the bottom cut out and split down one side. I taped the side closed and clamped the bucket to its lid that supported the head. I placed a small, waxed board on top of the flange to keep the silicone mold from lifting up as the foam expanded. Finally I mixed Part A and Part B foam in a container and poured the mixture inside the bucket down to the bottom of the head. It expanded to the top of the bucket to make a support mold.

After the foam expanded and hardened, I removed the clamps, sawed the top of the foam level with the bucket, removed the tape and pealed the bucket back so I could pry the two sides of the latex-foam mold apart.  Before separating the mold, I drilled two holes through the mold near the top above the head and pushed a wooden dowel in each hole to keep the two sides aligned when I put them back together after I removed the clay model. I tested a little foam mixture in a glass jar to see how much it would expand. It expanded about 20 to 1.

It took some effort to remove the flanges, pull the two sides of the mold apart without separating the foam support mold from the silicone and to remove the clay model that ended up pretty much destroyed.