3" bubblier to fit inside a PVC mold.  The hole will mount on the side, this way your can use bottles and extensions to center each layer.  I will have to redisign for the 2.75" disc.  At this time I only have the 3" in the side mounts to fit the 6-32 rod.    Each acrylic disc is cut with a laser. There is paper on both sides that peels off.

Pull Through Disc Bubbliers Soap Making Tool Technique Side mount