Hello. I am preparing my external weatherboard for painting. The old paint is quite flaky. I have sanded a section of it multiple times with 80 grit sandpaper to start. It appears smooth, however after about 24 hours later the smoothed area seems to be flaky again. (Before I get to prime and undercoat it). See the photos. Should I be sanding it back to the bare boards, or use a product like "Peel stop" by Zinzer? or another similar product? If I use a prime undercoat on the surface with slight peeling, will this continue peeling? Any suggestions are welcome. Cheers...Darryl
