In order to sand the steps and get a second coat of paint on I had to bake the steps. Dennis gave me the idea and it worked a treat. I made a temporary oven by leaning 3 sheets of play to form 2 walls and a roof and then draped plastic sheeting over each end and placed an electric heater inside (actually half in half out so that the thermostat would not cut the heater off). It got to 50 degrees C inside and after a few hours inside this it was hardened. I sanded the runs out of the risers and water bubbles out of the treads with wet and dry 400 grit.
The light in my shed at night even with strong Halogen lights is not great for painting white on white so to avoid getting runs in it again I decided to wait until the next morning to spray the second coat. Unfortunately, so paranoid about getting runs again (as I had no time left to cut them out and coat a third time) and inexperienced at spray painting, I gave the second coat a very light coat. The end result (after another stint in the oven so that I could transport the steps to SC boat show the next day) was that I did not give a thick enough coating in order for the paint to self level into a smooth finish. I had what could only be described as more of a splatter covering of paint. It was glossy in parts and spotty in others. I looked OK, but I now know I can do much better than that. Having said that I doubt I will want to paint my own boat. Painting is crucial to getting a great looking boat and I doubt I could get a good enough finish.
But one thing that the painting exercise taught me was that I am capable of getting a good fairing finish. You never really know until you have a coat of gloss on, but after applying paint to the steps I could see that in all the critical areas, such as along the coves, around the curved edges and across the front of the curved risers. It also showed me how fine a job needs to be done. The slightest blemish will show up like a neon sign with gloss white paint on.