I've been making a few parts experimenting with cores as I go.  I'm favouring 200g/3mm pvc foam/200g OR 200g /3mm soric/200g.  I'm finding they feel equally stiff and weigh pretty much the same.  Obviously the soric cell is fairly soft but the structure makes it rigid.  The foam is harder but doesn't have the structure.  Has anyone performed break tests or have any other info that might discriminate between these two?

I am not aware of any direct comparison break tests.

However your initial impressions seem about right in terms of stiffness.  Normally we would expect the soric cored material to be slightly heavier due to resin uptake during infusion filling all the voids with resin.

Also remember the cores primary function is to keep the 2 layers of laminate seperated thus the structure can take a higher load. On relatively small laminates like yours, the core may well be stronger than it needs to be ie the skins will reach thier limit before the core fails. Thus differences in the cores may not seem so apparent.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Thanks warren, some interesting things for me to think about