How long does this take to set up

Thank you for posting your inquiry. As indicated on the product package label and supporting product literature : "Apply up to ¼ inch and let dry approximately 6 hours to a hard consistency (longer in cooler and/or humid conditions). For thickness greater than ¼ inch, apply in multiple coats allowing each coat to dry completely between application. Feather edge all applications to ensure a smooth surface. Maximum application depth is ¾ of an inch."