The best materials testing information I could find was by the Swedish Navy
which were doing meticulous panel testing for their upcoming high speed patrol boats. They tested all the core
materials, e-glass vs s-glass, and the various resin formulations. They did it with both vacuum bagging wet layup
Then they subjected the panels
to various torture tests including maximum impact drop testing and repeated lower intensity cyclic loads simulating wave strikes.
The clear winner was Corecell M with epoxy
resin infusion giving a 1:1 resin to glass weight ratio. The epoxy
was, from memory, SP Systems which had a high "toughness" characteristic (no micro-cracking). We also tested West Systems vs SP and found the same thing.
was down the list and had inner skin delamination
, because it's compression
modulus is so high. The force gets transmitted through the balsa to the inner skin, particularly where there are longitudinal members or bulkheads that restrict the panel being able to flex. So in this case, more is not better.
There is a big move in the high performance watercraft field to be using the Diab HM or Corecell M for this resistance to delamination
, check it out yourself.