I have a few questions about painting some new masonite doors I purchased. First a little background before I ask my questions. I did reprime the new doors with Zinsser 123. The primer laid down great with no brush marks. I am using a Purdy XL paintbrush to paint the doors. I am also painting the doors lying flat in my cellar where it is cool and out of any direct sunlight. My first coat of paint (Acer Royal) went down nicely on top of the 123 primer. However after a day or two of that coat drying, I am applying my 2nd coat and the brush is dragging very badly. Thought it may be my brush so I took out a brand new Purdy XL I had and it is doing the same thing....therefore, I have ruled out any brush problems. I added some Floetrol to the paint and that did help, but it is still dragging.