IMHO ,not a pro just a DIY tinkerer:
FOAMS
Hundreds of XPS builds in the FBook Board and Hydrofoil building group.No issues with delam that i have heard so far.
Euro XPS is heavyish at 33kg/m3.Needs hollowing or Ultralight lam to give decent final weights.
With light lam i got a SUPfoil 6.8x27.5x 110ltrs at 5.5kg with pad.
With hollowing i think next build will be same dims but 4.5kg.
US XPS (Foamular 250) is great at 25kg/m3.Wish i could get it.
EPS is the lightest foam…but sucks water.So it needs heavier lam and very careful finish (hotcoat).Any pore or tiny ding can turn board into a waterlog.Many people are riding 2000$ Carbon EPS boards with a kg of water inside…weigh your board new and check it if it feels weird.
LAMS
-Carbon has the best traction/weight properties,but it sucks at impact.Beware of spread tow, great properties but very hard to work.
-Sglass is middle of the road in both, but it sucks resin.Easiest to work with.
-Innegra is superlight, cheap,sucks little resin and excels at impact.Not so good in traction and difficult to sand.Way easier to work than Kevlar (and kevlar sucks water ,Innegra does not)
Carbon and Innegra are a great combo.
We only need stiffness in the stance area.
Nose and tail are just volume and Hydrodynamics.
BUILD TECH
Vac bagging works very well to get light weights but can be a mess of laminate wrinkles and a waste of materials (peel ply,absorbent) , Jimmy Lewis made some great vids for the FB group with the Poor Mans Vacuum system.I will try it on next build.Very promising.
This are just some random ideas ,check the group,just for the Jimmy Lewis vids and the hundreds of weird,wonderful and crazy ideas it is worth it even if you loathe FB like i do… 