I've been using a friction chuck to fine tune and sand the outside of bowls. One uses 4" PVC pipe, another smaller one I turned from a piece of wood. I used a piece of router pad for non-slip padding to protect the inside of the larger bowl from the pcv, but it left an oily ring on the wood (like the mark some plastic jaw clamps make on wood), which may or may not be visible after finishing.
On a smaller bowl tonight using the wood chuck, I tried covering the pad with a blue shop paper towel, but it was too bulky, and wouldn't turn true, so I went with just the paper towel folded several times covering the chuck. As I was fine tuning prior to sanding the outside, I could feel the bowl slip a few times, and when done sanding, sure enough there was a ring scuffed into the inside of my nicely sanded bowl.
So my question is, what is a safe padding material that won't slip, and won't transfer any bad boogie to my work? I'm sure that some of the high friction rubber or plastics are safe, but which ones won't leave an oily sort of mark?
Thanks,
Dan