limit of about 200 m min with no apparent change in bond strength or quality of the single faced product experience has shown that board made under similar operating conditions in which the spreader element was omitted would rarely have a pin adhesion value above about 380 n and that values this high could only be obtained with increased adhesive useage when a more conventional adhesive applicator was used with this product such as that shown in commonly assigned u s patent application ser no 836 181 filed sept 23 1977 it was necessary to use adhesive spreads in the range of 8 to 10 g m 2 to obtain adhesion values in the range of those in the present example this represents over a 50 increase in adhesive useage one previously unsolved problem with hot melt corrugating adhesives has been stringing between adjacent flute tips this spider web like effect is quite wasteful of the expensive adhesive about 20 of the applied material has been rendered non functional in these strings quite surprisingly the present extrusion head has almost completely eliminated flute to flute stringing the reasons for the beneficial effect are not well understood the extruder head has also been found to be an effective adhesive applicator in the corrugating process with materials other than hot melts as one example a corrugated board was successfully made using a conventional aqueous starch adhesive having approximately a 34 solids content.