Wow.... we're using the exact same thing! Maybe it's just because I do this in my basement where it's more damp than the rest of my house? Do you live in a dry area? Sometimes northern VA can be humid... I've made 4 or 5 different molds so far and I get the same results each time.... arrrgh....

How are you making your molds? Pouring or brushing? I poured my molds.... perhaps it has something to do with the density of the silicone itself?