Out of interest what are you using to paint it black? Or do the powers that be specify that too? I'm quite a fan of Bedec barn paint. Never ever come across a product that covers, so well, timber on the FIRST coat. Seemingly ticks the environmental boxes too. http://bedec.co.uk/BARN PAINT LEAFLET.pdf That being said I always used to use Sadolin way back when. Seem to remember it took an age to dry. Bedec, 3 coats in a day no problem.