Here is my first effort using Hydrocal. It’s a large pile of skulls.
So, to make this I just got some clay, made a rough inverted cone and then took some skulls I have mounted on sticks to poke into the clay all over the inside of the inverted cone, then I mixed up the Hydrocal and poured it in. When it set I just peeled back the clay. Nothing to it.
And here is an attempt to use Hydrocal to make a miniature.
It’s the mushroom man on the right. You can see that the base broke when I demolded it. Also the left arm fell off and I accidentally set something down on it, crushing it completely, so the left arm here is made from green stuff. This Hydrocal stuff is pretty fragile, I doubt if this mini will survive any vigorous gaming table sessions. I painted it with Future floorwax and then painted it, then dipped it in varnish, so it’s a lot stronger than it was when it demolded, but it still feels very fragile.
I actually think the Hydrocal picked up the detail of the mold pretty well. Much better than I had expected.