I have finished fixing the area under my deck hatches and decided to finish it off with a little gelcoat to make it look nicer even though no one will see it. I followed the instructions on the can and added the hardener following the guidelines for our temperatures here ( ~80 degrees ). The gelcoat did not set over night. I applied it with a foam brush and I'm wondering did I lay it on too thick or should I do it again and double up on the hardener? I was using the same stuff I used last summer, does this stuff have a shelf life?