Brush-on (glove) molds for big or complex objects

For a 2 ft sculpture, pouring a block mold would cost $300 in silicone. A brush-on mold uses a thin layer (3 to 4 coats of thickened silicone, about 3/8" total) backed by a rigid mother mold of plaster bandage or fiberglass. The silicone peels off like a glove and the mother mold holds its shape for casting.

Thicken silicone with Thi-Vex or fumed silica so it stays on vertical surfaces. First coat thin and bubble-free (the detail coat), later coats thick. Add registration bumps on the last coat so the mother mold locates. Plan the mother mold in two or more pieces with flanges so it comes off.