I found these Norton Blaze discs really good at stripping and surface conditioning exterior surfaces recently. Flaky painted fibreglass or peeling paint on wood, the discs quickly took it back to bare substrate. I had a 50mm and 125mm one. They don't last as long on metal, I stripped paint from a small lamppost and that was it worn out . For softer substrates I had a 125mm one that lasted a house. Think of them as a really coarse non clogging abrasive. You can get them pretty much anywhere Screwfix and Toolstation sell them.