Here is another take-off on inner tubes method. Buy a bicycle inner tube from Wal-Mart
or other such place, cut off the valve assembly, and then split tube length wise, it makes
a very effective,strong clamp that will stretch and stretch all you want or need. I use mine pretty regular on re-gluing chair legs and other odd glue ups where normal clamps won't even get close to holding. Try this...it works well!