Abstract: A method of making a honeycomb structure includes the step of intermittently slitting a sheet of material such that longitudinal slits are aligned in alternating staggered rows. Each staggered row has a lateral centerline spaced substantially uniformly from adjacent row centerlines. The longitudinal slits in each staggered row have substantially uniform lateral spaces between each slit. Another step is applying continuous stripes of adhesive laterally across a top side and a bottom side of the sheet such that each stripe is spaced apart longitudinally and centered on a row of slits. The stripes alternate between the top side and the bottom side. Still another step includes pleating the sheet such that pleats run longitudinally. Each pleat has a top fold and a bottom fold aligned with a longitudinal slit. Yet another step involves gathering the pleats together in a closed stack and compressing the stack to cause the stripes of adhesive to bond the pleats together at adhesive contact points.