My 2" cylinder imbed molds have been splitting lately. The soap cylinders 2 sides split open in parts and do not unmold in perfect rounds and tend to crack the soap as it opens the mold in areas. I even try to rubberband 3 -4 spots to hold it together before I pour and keep it banded for a few days. The molds are snapped tight together. recipes not very different than what I have used in the past but seems to happen pretty often. Any ideas why? Would love a perfect cylinder that doesn't split open the 2 sides of the mold!