Looking for some advise. I made some foam rocks covered in grout, left to dry 3 days. They came out nice. Then I tried to seal with polycrylic water base matte finish from minwax. However after one thin coat it dried milky white (and yes i stirred well). After 24 hours and no change i sanded and applied water base polyurethane. The polyurethane seemed to dry clear, but they are still very cloudy from that first coat. Does anyone know what i did wrong? Also, if I paint the rock now with acrylic paint, could i just add more layers of polyurethane, or would the paint make the polyurethane not adhere correctly? Thanks for any help.