When I purchased a 36″ radius platen from Bill Behnke to do some S-Grinds on my chef knives, the grind didn’t turn out how I wanted. When I was working on making a sanding stick to match the radius, a coworker who was big in 3D printing Josh Hoffman said “Why don’t you try printing one”. Using some of the knowledge I had from making my flat hand sanding sticks, we started on the prototypes. Once I had a design I liked, we printed some and I put all of my force into it and test it for strength. Needless to say, it held up very well to the abuse of hand sanding.
I use double sided tape from McMaster Carr (PN: 76405A13) to hold the sandpaper on the stick. I did an IGTV video where I showed how I use the Sanding Buddy.