i haven't actually done the math, but its hard to argue with the success other folks have had with surfboards.
i agree, its hard to believe swapping core material with something softer will improve the strength/stiffness. But, it may allow the board to withstand higher flexure limits
almost out of necessity, thin boards are required to flex alot.
the more the flex the greater the shear and related shear elongation.
even though we design the skins to carry all of the associated tensile/ compressive forces of a flexible board its still possible to exceed the flexure/shear limits of the core.
possibly, the shear stress is not
too high for the H80 but the required shear elongation is.
i think this may also be related to some folks having better success with more elastic Airex cores. In particular, when using lighter layups.
maybe that is a much simpler solution than a full sandwich layup?
there is a pretty cool thread talking about what others are trying.
http://www.swaylocks.com/forum/gforum.c ... ost=183391
lastly, i should appologise for completly hijacking this thread.