After the previous coat took over three days to dry, I was leery of adding the second coat. I grabbed the cans of paint and hardener to read them and make sure I was using the correct ratio. That's when I discovered that I had used acrylic hardener in epoxy paint. To be fair, the cans had identical graphics, were part of the same line of paint, were sold right next to each other, and there was no other hardener types on the shelf when I bought them. Still, I felt like an idiot, and fortunate that the paint had actually set--eventually.
I scuffed the first coat, mixed up another batch of paint (with the proper hardener this time), and carefully hand-brushed a second coat onto the surface with a smooth art brush. I'm hoping this is all I'll have to do on this project. We'll know tomorrow.