I got some fun foam from Michael's to add to the tip (between wood and sandpaper) to get better contact with the sand paper, seems to have worked. I've used this sander on a blade and I think I used too much pressure in my tests. Just like and orbital sander, simply guide the tool around and let the vibration do the work.

I really like the way it works and it keeps me from using too much pressure on the blade. With the right grit sand paper it removes red rust like some magic eraser. I'll have pictures coming soon of my first restore using this tool.