"I wish I had a more optimistic pov but unfortunately I'm redoing the tops of my deck railings as we speak, after two only Winters...I'm not happy."
I followed all the instructions on the product label; I bent over backwards to ensure a long life...5 yrs. minimum I thought was reasonable. I remember in the long ago past, linseed oil based paint, you'd get 10 yrs on a deck railing.
But I digress, this c**p I used is called 'Sharkskin'. I replaced all the railing caps in Aug. 2016. Air dried Cedar, tested the moisture content, around 12% ...Sharkskin is approved for up to 20%.
Overpriced waste of time and money, in my opinion, based on it's performance on the WR Cedar. I'll try and find the pics I took before I belt sanded it down a couple of weeks ago. I got up at dawn this morning and got a fresh coat down at 7:30AM. It was dry to the touch by 9:00AM; I'll do a second coat tomorrow same time.
The pic below is what it looked like in 2016 after installation and painting. (I hadn't done the rest of the railing yet. In fact I used an acrylic exterior solid stain on the rest of the railing and it's held up just fine.)