How does he do this? (Resin Infusion)

Resin Flow Mesh

You should use VARI systerm . Resin Distribution Net, or Flow Media, is most commonly used for vacuum assisted resin transfer molding and resin infusion. Composite bridge decks using SCRIMP technology is one of many examples. The recognized advantage of our media is that is will increase your resin flow rates, in return, reduce your material and labor costs.
my email: markchinawire@yahoo.cn

 

What about the gas from the epoxy foam, in the second method, it won't bugger the laminates?
Does this method compress the laminate well? Do you make exit holes for excess resin/gas?

How much diagonal (assuming +-45') in relation to longitudal, for a 18cm chord, 10% thick, 120cm long board? Probably 4mm wall thickness.

I'm planning to stitch tow to braided sleeve, then pull another sleeve outside, and stick a bladder inside, put in mold, and pump.
Possible modifications: 1: Use uni sleeve from soller instead of tow (but I already have the tow)
2: use two bladders alongside, each with a braided sleeve around it - to make a shear web.

 

Gas is not a problem, it is contained in the foam. If it would escape the foam, the foam would collapse. It does compress the laminate somewhat, but not impressive. No exit holes, weigh your materials, and experiment a bit, or overfill slightly.

Layup: no idea.