If there is someone out there with a hot glue gun, what do you think
the chances are of it sticking the spine of a paperback book, e.g. 350
pages? I've looked at a number of paperbacks and they are all glued,
like the Argos catalogue, for example. The pages could be roughened at
the binding edge, held in a clamp of some sort (easy to make), and the
hot glue applied.

Another idea I had was to use iron-on edging strip.

MM