This was a little while in coming because I wanted to clear it with the Roveras first. Watching Dorelio was amazing; he works so effortlessly. The disk he's shaping on (at about 1:40 in the video) isn't sandpaper; it's a specialized metal disk that his grandfather made, which they've never been able to get a machinist to replicate. I've only ever seen one other workshop where the primary shaping disk was metal rather than sandpaper, and that was Lars Ivarsson's. The actual style of the two disks couldn't be more different, the idea is the same: in the hands of a really experienced pipe maker, a rougher, more durable surface allows for more accurate, faster work. Of course, one misstep and one destroys what one is working on, and perhaps loses a finger.