Can you put wet clay on top of hardened clay?

Yes, you can put wet clay on top of hardened clay, but it requires proper surface preparation for good adhesion. The hardened clay should be scored or roughened to create a mechanical bond, and it's often helpful to moisten the surface slightly before applying the wet clay. However, if the hardened clay is completely dry, it may be challenging for the wet clay to adhere properly, potentially leading to cracking or separation as it dries.