The hook pad on my multifunction accessory got destroyed when I wasn't
paying attention and ended up sanding with the sandpaper fallen off.

I could by a whole new accessory but I would rather just replace the
hook side of the velcro (which is attached by adhesive).

I tried using a piece of heavy duty brand-name velcro. But while the
adhesive held well to the plate, the hooks didn't hold the sandpaper
very securely.

So, it seems like it might require a 'different' hook configuration.
Anybody have any suggestions where to get good replacement hook-velcro
that is adhesive backed and mates well with 'loop' sandpaper?