If only I knew what was inovolved when I decided to strip the robot's knees down to the wood and re-finish them. Since there were multiple layers of bumper rubber paint AND Plasti-dip AND paint, the job was a mess. The sandpaper clogged up immediately so a file was used to scrape the stuff off the wood. After about 3 hours, the knee still looked pretty sorry. But the alternative to redoing them is to leave them looking rough. At least I know another guy in the B9 club that had a similar knee experience.
Instead of doing the second knee the same, I decided to hunt down a sandblaster and sandblast them. My son said his roommate has a sandblaster I can borrow.
I also sanded the tread section and prepared it for repainting. It was satisfactory as it stood but I figured it won't be much more work to repaint and fix some of the marginal areas. I also sanded the knee plates and prepared them for repainting. Might as well do it right.