From my limited experience with eps sealing is important particularly with lighter grades and especially with block foam which most people use. Well fused moulded eps does not require sealing as put simply it has no room between the beads to soak air, water or resin. To machine there is no tear out or tape required to hold the blank down on the machine. They fine sand well and look like PU shaped.
The downside is that they are not available in Sup yet.
there are laminators that don't seal, claiming less delaminations. they top coat twice as the resin goes off- fills in those 'air bubbles' that could be there. might not be as light, but they feel the bonding is better
cheers
epoxy to expoxy is one of the best bonds ever its crazy stuff with normal surfboard resin i get it on my fingerfails and it comes of super quick i got some epoxy, a drop on my big toenail a couple of months back and its still hanging in there?
Yes it really depends on what grade foam you are using the heavier grades you can get away with not sealing but with what im using sealing is a must and is a big reason why i can keep the weight down to around 5.4 kg
. i think they are thinking about the epoxy to foam bond. by not sealing, the epoxy/glass main coat 'hooks' into the foam. i would seal myself if i was a laminator
