So far I have brushed my chassis,the underside of my floor,rear cab (below the window) and the inside of my roof. There are no visible brush marks.
As Ed said, watch out for bristles and make sure your paint area is as dust free as you can get it.
POR-15 dries as hard as nails and covers really well(80% solids)
Mix it well and don't overload your brush,so sags and runs shouldn't be a problem. A little goes a long way!
Check out Alan's pics. Nice job!
Good luck!
Jock.
