What is the difference between your hard molds and flexible molds? There are differences in our hard and flexible molds and it’s good to think about how you are going to use them to know which kind to get. It depends mainly on the type of casting you choose to work with as to what type you should purchase. Our hard molds are made of a clay that hardens when cured. They are very durable and can withstand a long life. If you look at our “basic instructions” on our website, you will see they work great with polymer clay as well as many other castings. Our easy instructions shows you how to use our molds with a perfectly flat back every time. Our flexible molds (found on the flexible molds page) are made of a flexible clay that is slightly flexible and allows for the casting to be removed easily. However it is important that you are careful when removing the casting, because the movement can produce a deformed casting. Be sure to read the instructions on the flexible molds page on our website for more details.