methods are disclosed for making a base of a spa apparatus to resemble artificial rocks and wood . in one embodiment , the method is comprised of the following steps : making a mold in which its inner surface has the shape and surface texture of a rock or wood ; placing a first structure on the inner surface of the mold , the first structure being operative to prevent warping of the base ; spraying polymer on the mold ; allowing the polymer to harden ; and removing the hardened polymer from the mold , the hardened polymer having substantially the shape and surface texture of rock or wood .