You can fiddle a lot of time away trying to clamp hexagons, octagons, or any of the other polygons you might build. A strap-type clamp is the easiest way to hold them for gluing, but what do you do if you don't have one?

Get a rope. Then drill two holes (rope diameter) through two pieces of scrapwood near the ends. Thread the rope (sash cord works great) through the wood, as shown right, and tie a knot in each end. Drill a dowel hole on an edge at one end of one piece and glue in a dowel, leaving about two rope diameters of it above the surface. Now, to clamp your work, place the wooden pieces three or four thicknesses apart and cinch the rope around the work, taking in the slack at the end near the dowel. When the rope is tight, pass its end around the dowel and back under itself to make a half hitch around the dowel. Then, draw the pieces together with a C-clamp or handscrew to tighten.
—Joe Bailey, Russellville, Ark.