Added My Wash Down & 5200 ?

[Stillrunning]

Well Hammer no pics as I'm still waiting for Panasonic to return my camera. I added a wash down this past weekend and used 5200 for the first time. My question is the directions state that it takes 7 days to fully cure and it also said something about 48 hours to set up. I used it on the thru hull below the water line and did not know if I have to wait the 7 days for it to fully set up? I also read that it is only good for use within a couple of day of opening. Is this the truth and whats left over now junk?