Here is my sanding board ready to use. Notice that I did not just plop down a whole sheet of sandpaper on the board and use 3 strips of carpet tape on wide spacing to hold everything together. I measured the limits that my board would move and used two strips of carpet tape side-by-side in the sanding area. I then cut the sandpaper to fit the carpet taped area. This gave me less wasted materials. I used approximately 90% of the sandpaper area rather than just a narrow strip.

The sandpaper is Norton Premium 120 grit.