I take 3 days to sandwich. I put down the batting and then spray adhesive the backing on it. Smooth not tight. Wait a day and then turn it over and spray adhesive the top. I wait another day and then safety pin it every two to four inches starting at the middle. I still manage to get one or two puckers but I figure it will get better with time. Clyde said not to pull it tight and I'm taking his suggestion.