When making a clay sculpture, how does one mould workable clay onto dry clay without it cracking?
Is your clay green ware or has it been fired yet? Have you tried simply moistening the dry clay with a sponge or wet towel then applying some ‘slip’ (super mushy clay) to the area so you could work said area into the desired shape and then let it re-dry. A good way to keep your clay from drying out in the future is to throw it in a large air-tight container like Tupperware or a glad-box. If you don’t want your sculpture to stay all mushy, you could also just try hanging damp paper towels over your work when you’re not playing with it.