You'll have to remove the cover pages to start. Then put scrap plywood boards on both sides of the paper block. Those boards have to be 3/4" wider than the paper block. Then, on the exterior overhang, srew the top board to the lower one(this one would have to be at least 3/4" thick to accomodate screwing) This will press all the paper together. You could also put screws in the waste part also.
You could also glue the pages together beforehand and press to make a block, that would shorten time. Then glue a pattern with the desired shape on top, drill a hole through the waste side and thread in a saw blade. Attach the blade at both ends in the saw, tension it and saw to the pattern. Remove the blade and sand the cut edges to level the miscuts. Bunched up paper behaves almost like wood so any treatment you do to it will have the same results. I do it with cardboard often. Instead of gluing you could also varnish or lacquer the edges, when dry it's almost the same.
Then reattach the cover and you're done.
You can get a decent scrollsaw for about 100bucks just make sure it has variable speed and you can use it to make tons of projects.
If you go the router way, get something better than a zip. Get a plunge router with pattern following bushings. And decent dust pickup!
